Post by 90GTVert on Feb 8, 2014 10:16:56 GMT -5
Chinese Scooter Assembly And PDI
Introduction : What Is A PDI, And Why Would I want To Do One?
Chinese scooters are infamous for their poor quality and the bad experiences of some of their owners. I, and many others, feel that this is largely due to substandard quality control by their manufacturers. Parts and systems aren't subject to the same scrutiny while manufactured or assembled as they may be in factories for Japanese, European, and Taiwanese scooters. Even though many of the parts for said scooters may be manufactured in China, it's sometimes said that you get what you pay for when you deal with Chinese manufacturing. They can produce quality products, but Chinese scooters are all about low cost and cutting back wherever possible. That equates to less precise tolerances, inconsistent parts, sometimes missing parts, lower material quality, and even damages during manufacturer assembly. It's also been said that Chinese scooter factories may use whatever parts they can source cheapest or happen to be on hand. It seems like this was more of an issue in years past, but it may still be a factor.
All of the above is amplified by the lack of good dealers and the large amount of new scooters delivered directly to the consumer in the crate. A new Honda for example would be manufactured with better parts and better assembly and better inspection. Then the new Honda would end up at a Honda dealer where it's met by a person or persons with the training and skills to perform a proper PDI. For a dealership, PDI would stand for Pre-Delivery Inspection. Meaning the vehicle is inspected before being delivered to the customer. In our terms, a PDI is usually called a Post-Delivery Inspection, because we, the customers, are the ones doing the inspection after the scooter is delivered to us. Back to the new Honda, it receives a series of checks and preparation by the folks at the Honda dealership before it goes onto the showroom floor or out to the buyer. Add to that the fact that the Honda will probably have a much better warranty and a staff of trained mechanics on hand to perform warranty repairs and other work.
A new Chinese scooter does not frequently get the same attention. Of course it likely starts off with less than ideal materials, tolerances, and assembly as mentioned. Then it gets crated and shipped out. Very commonly, Chinese scooters get shipped direct to the customer's door and you probably don't have an experienced mechanic just hanging around your home waiting in case a scooter pops up to be inspected.
Even when the scooter is shipped to a dealer who will sell the scooter assembled, not all dealers are equal. There are Chinese scooter dealers that try their best to deliver a reliable product to their customers and thoroughly inspect and service Chinese scooters before they make it to the customer. I feel dealers with that level of care and attention are the exception rather than the rule when dealing with cheap Chinese scooters. Look around locally and online. You can find tons of stories of dealers that don't know how to service the scooters they sell, have difficulty locating parts for the scooters they sell, don't make scooters their priority, go out of business, etc... It's not hard to find a used car dealership, thrift shop, and all sorts of other businesses with Chinese scooters out front. They obviously don't make the scooters their priority in many cases. The scooters represent a quick buck to many of them, and good luck getting proper support from that type of dealer.
Also add in that Chinese scooter manufacturers don't generally offer warranties that cover the range of things that Honda for our example covers. Even if the warranty covers a defective part, all repairs are usually required to be performed by an authorized professional and warranty must go through an authorized dealer of the product. Some of the folks selling Chinese scooters are not even authorized dealers, but rather they buy a few in the crates just as you or I could and resell them locally to make a quick profit. I don't know about your area, but in mine I can find people operating a "dealership" out of a rented storage locker.
Now we're dealing with a lower standard product with little to no dealer support in many cases. Of course making an educated purchase can change this. Do your research before buying. Can't deal with repairs and maintenance? Consider the big name brands. Wanna give a Chinese scooter a shot anyway? Spend some time researching different manufacturers and brands and see if you can find one with a better reputation. Research local dealers and go visit a few before you buy anything. Talk to their customers and see if they're happy. Have a good look at any Chinese scooters you can find for sale and go look at Japanese, Taiwan, and European made scoots as well. Pay attention to detail and you will likely see some of the quality differences for yourself. The more educated your decision, the greater the chance that you'll be a happy scooter owner.
This article isn't really about buying a scooter though, so lets get back to the topic at hand. After you've purchased a Chinese scooter, one of your biggest opportunities to improve your future experiences comes when you are assembling the scooter or just after you've taken delivery. That's a PDI. Performing a PDI can solve some problems before they occur. A PDI may mean you ride with a smile instead of standing with your broken down scooter on the side of the road. This is not to say that a PDI eliminates all future problems or performs a miracle and makes the metals and plastics any better. It certainly will not. However, you can lessen the probability for certain issues by performing a thorough PDI.
Before getting into the details of a PDI, I want to touch briefly on the inspection upon delivery for scooters that are shipped. Before you place an order, make yourself aware of the seller's policies regarding shipping damage and claims. If you are unclear on how to handle a scooter that shows up damaged, call or email and ask someone before you buy. If possible consider contacting the actual delivery company to find out their policy on shipping inspection and damage as well. Everything you find out will be of no use at all if your scooter arrives in perfect condition, but if the door rolls up on the delivery vehicle to reveal a mangled crate, you'll be very glad you made the effort and know exactly how to handle the situation.
I would suggest that even if you don't make yourself aware of the procedures required, at least inspect the crate and scooter before signing the delivery receipt. This is not to say pull the scooter out and begin assembly. Note any damage to the box in the deliverer's presence. It may be in your benefit to have camera handy to take a picture of a damaged box before it is ever opened. At least open the top of the box for a look in for any obvious damage. Some crates are boxed without a floor so the cardboard can be easily lifted up and out of the way for a clearer view of the scooter. In other cases a couple of cuts with a razor knife will quickly allow a good look, but be careful not to damage anything while cutting the box. Do a quick walk-around and again note any damages to the delivery driver and make sure they are noted on the receipt before signing.
Report any damage to the scooter to the seller immediately. Do not wait long because many shippers require notification within a short time after delivery if they are to accept a claim. Again, I don't know the rules as they vary, but educate yourself for your own protection.
Performing A PDI : Video Series
I've made a series of videos, totaling 1 hour and 49 minutes, that goes over the major points in a typical Chinese scooter PDI. The videos are broken into multiple parts so that you can watch the whole series or pick and choose based on what you already know or don't know about the process. The video titles and descriptions should let you see the more specific topic of each video all the way from uncrating till it's ready to ride.
Performing A PDI : List
I feel that the video series provides good coverage of the average PDI process in a step by step manner from beginning to end, but here is a list that you may also wish to refer to. This list is not ordered in a step by step or chronological fashion, but rather in categories. Even if you have followed the videos, it's not a bad idea to go over this list. I have included some checks and details not in the video series.
A YouTube viewer informed me of his troubles selecting just the right items for his PDI. He suggested that I include help with choosing common items in case others experienced the same difficulties. I have included quite a bit of parts and supplies info in the list below, and farther down the page are links to tools. This is not necessarily a complete listing of everything you will want, and many items you may not wish to use. I feel that if you read this entire article and watch the PDI videos you should have a lot of information to begin forming your own personal shopping list. If you still have questions please join the 49ccScoot forum to ask and we will do our best to assist you. You certainly don't have to buy from these links, but if you are unclear on what you need, hopefully this will offer some guidance. Many of these items can be found locally in auto parts stores, hardware stores, Harbor Freight, and even department stores.
Please report broken links via PM to 90GTVert .
**I do not have personal experience with many of these exact items. Please do further research before making purchases. Read reviews of products, specifications, and all available information. It is your responsibility to buy what's right for you and to ensure that any tools, parts, or supplies you order are compatible with each other, your scooter, and your needs.**
Body Panels And Accessories
The body panels should be removed near the beginning of the PDI to allow a clear view and access to the engine, wires, hoses, and so on. Remove panels with care. Most body panels use not only screws and bolts to secure them, but also clips, tabs, and grooves that interact with other panels. Look over all angles of the panel before attempting to remove it to be sure you aren't missing any connections. A little extra time and care now can save rattles and loose panels in the near future. Be mindful of wiring connections that may be attached to the panels as well.
Inspect all panels for cracks, broken tabs, or other forms of damage. PLASTIC WELDER is a two-part adhesive that usually works well for repairing scooter plastic parts, though it does not adhere well to the black ABS plastics (such as the leg shield or floorboard) in my experience. There are KITS FOR WELDING PLASTIC too, but they are kind of pricey. If you are skilled with fiberglass repair that's another good option.
Many scooters use speed nuts or tinnerman clips on panels to allow other panels to be fastened to them. If they are loose fitting, you may wish to squeeze them together more with pliers to get a tighter fit. Some like to add silicone or other mild adhesives to the clips to help keep them in place.
Consider cleaning and waxing the body panels before re-installation. You'll probably get fingerprints on them while re-installing, but it's easier to wax them now than once installed in some cases and the fingerprints should wipe off easily after the panel has been waxed. Soap and water cleaning will do the job in most cases. I'd suggest hand waxing vs a buffer. Some panels are a bit delicate and can be burned easily with high speed buffing. Unpainted black panels should be cleaned and can be treated with Armor All or your choice of protectant instead of wax.
When it's time to re-install the body panels, use the same care that you should have for removal. Check that all clips and tabs are lined up before trying to snap, screw, or bolt anything in place to avoid cracking a panel or breaking off tabs. Don't forget to connect any wiring that was disconnected from the panel during removal.
Bolts should have thread locker applied before installation and torqued to proper specs. Thread locker comes in a variety of makeups for various tasks, but the two most common are BLUE MEDIUM STRENGTH and RED HIGH STRENGTH. Blue works for the majority of needs on scooter fasteners. You may opt to use high strength if medium strength doesn't work, but high strength can make fasteners very hard to remove.
Use washers and rubber washers where appropriate to help spread the clamping force better and to help dampen vibrations.
You may wish to apply silicone to screws to help keep them secure. Be careful not to over-tighten screws going into plastic panels.
Select the proper left and right mirrors and install them into the control switch assemblies on the handlebars. They should have a nut on the threaded end. Screw that all the way onto the mirror, no need to tighten it yet. The mirrors should just screw into the threaded spots on the controls. Use thread locker on the mirror's threads. It's usually best to sit on the scooter and adjust the mirrors before tightening. Once you have them adjusted, tighten the nut down against the control assembly to lock the mirror into place.
If you will be using a trunk with your scooter, it should mount to the rear rack. Find the holes in the floor of the trunk that line up with holes in the rack and install the provided hardware to secure the trunk. Use thread locker on all bolts.
Wheels, Tires, Brakes
Verify that tires are installed on wheels in the proper orientation. Many scooter tires are directional. These tires will have an arrow indicating the direction the tire should rotate for forward motion. If the arrow does not match up to the proper direction, the tire should be removed and re-installed in the proper orientation.
Install the front wheel. You usually have a plastic piece between the brake pads that must be removed. There should be a spacer on one side of the wheel and the speedometer sending unit on the other. Line everything up, get the brake disc into the brake pads, and install the axle. The speedometer sender usually has a receiver area on it that must align with a nub on the fork. You may need to tap the axle with a rubber mallet, but keep checking alignment and avoid pounding the axle through with a lot of force. Use thread locker on the axle bolt and apply proper torque.
Spin the front tire with the front of the scooter off the ground. Listen for excessive noise and see if there is any binding. If either are heard or felt you will need to check for clearance around the wheel and tire, contact with brake pads, wheel bearings, and proper spacer installation.
Check the tightness of brake system bolts. You may wish to remove them and install thread locker before re-installing with proper torque. Do not remove the brake hose bolts, because brake fluid will drain and you'll introduce air into the hydraulic brake system which would have to be bled out.
Verify that the fastener(s) securing the rear wheel is tight and that the wheel is straight relative to the engine.
Replace the stock valve stems. Use higher quality stems from a local tire shop or online retailer. Valve stems can be changed with the tire still on the wheel. Remove the valve cap and valve core. You will need a special tool for the valve core, sold at any auto parts store. All of the air should rush out. Use a C-clamp to break the bead of the tire by squeezing it. Reposition C-clamp so it pulls the tire to one side of the wheel, using a rag to protect the wheel. Don't place the clamp on the rim/lip of the wheel or it may bend. The old valve stem can be pulled out with vice grips, pliers, and/or the rubber underside can be cut away for easy removal. Depending on the style of new valve stems, they can either be pulled into place until seated properly or secured with nuts and washers/seals. Remove the C-clamp and move the tire back into position the best you can. Use an air compressor or air tank to pump the tire up (with the valve core out) until it seats on the rim. Install the valve core. Inflate to manufacturer's specifications, usually 32-36psi. Install the valve cap.
Most Chinese scooters should be able to use 0.453" / 11.3mm valve stems. You may be able to use short STRAIGHT VALVE STEMS on some wheels, but many will need 90 DEGREE VALVE STEMS for clearance and easy access. I'd suggest skipping rubber based stems and using metal stems (rubber seals are fine). If you want something with a more custom look there are options, HERE'S ONE.
Check the operation of both the front and rear brake. This should only be done after the front wheel has been installed. You should have a good "lever feel". The brake levers should feel firm, but not tough to depress, and you should not be able to touch the handlebar with the lever using normal braking force. The wheel should spin freely with no brake applied and be firmly stopped with the brake applied. Hydraulic brakes will likely need to be BLED if they feel weak and possibly have brake fluid added. Some favor replacing the stock brake fluid with fresh DOT 3 or DOT 4 brake fluid. If you have to work with brake fluid avoid getting it on anything, because it can strip paint and cause plastics to become brittle and eventually crack. Use rags or a container below the reservoir when filling, just in case fluid is spilled.
Drum brakes have a cable wit a nut on the very end at the wheel. Tightening that nut will apply more pressure to the brake. Loosen it if the wheel won't turn freely when off the ground.
DISC BRAKE QUIET can be applied to the backs of disc brake pads and the points where they contact the caliper. This may prevent brake noise. Apply a thin coat and do not get it on the friction material of the brake pads. BRAKE CALIPER GREASE can be applied to pins/pivot points.
Steering And Frame
Install the center stand arm/extension if applicable, using thread locker on the bolts.
Check the steering for play. You should be able to move the steering left to right freely. There should be no up and down of front to back play. Tighten the largest cap nut first to get the correct feel as described. Tighten the nut above it against the cap nut to lock them into position. If you cannot get the proper operation, you will need to disassemble the steering stem and inspect the bearings and races. Be careful not to lose any bearings. GREASE before reassembly.
Install the handlebars if you are doing an assembly. Use thread locker on the bolt and apply proper torque. The handlebars should have no play.
Remove fasteners not already dealt with one at a time. Inspect each fastener and replace or repair as necessary. Apply thread locker and re-install with proper torque.
Check the firmness of the front and rear shocks/forks. They should not bottom out under normal loads and should rebound on their own. You should see no fluid leaks from the shocks. The rear shock(s) would need replacement if functioning improperly. The front forks may be able to be serviced.
Look for rust or evidence of rust below the paint (bubbling). If rust is found, sand, clean, and paint. I've had good results from DUPLI-COLOR SATIN BLACK WHEEL COATING on the frame. It matches the standard black of most frames and has held up better for me than other paints.
Some trikes use ZERK FITTINGS to allow lubrication of some chassis points. You will need a GREASE GUN and compatible TUBE OF GREASE for those. Wipe off the grease fitting. Push the grease gun onto the fitting and give it a few pumps. When it's full you'll usually see grease starting to come out of a point nearby. Clean off any excess grease from the fitting and that has been pushed out.
Wiring, Electrical, Cables
Fill the battery with the electrolyte provided with it. This is acid, so use safety gear such as gloves and goggles and don't get any on yourself. Install the cap(s). Let the battery sit for at least an hour so it may begin it's natural charging process. Attach to a 0.75-1.5 amp float charger, such as a Battery Tender, until it is fully charged.
Inspect the wiring harness. Look for any signs of damage, wires and connectors not attached to anything, loose connections, and anything out of the ordinary. If wires or connectors are found disconnects, search for nearby connectors that match up. Wires leading to nothing should be either removed from the harness or have the ends wrapped with ELECTRICAL TAPE. Connectors leading to nowhere can be taped over and secured to the harness.
Inspect the throttle cable and brake hoses and cables for damage and repair or replace as necessary.
Disconnect each connector, one at a time. Apply dielectric grease to the connector and reconnect. DIELECTRIC GREASE helps to keep moisture out and prevent corrosion. You can get it in single-use pillow packs labeled as BULB GREASE as well, but you may want to pick up a couple. You can use CLEAR SILICONE to seal moisture out of connectors or other areas where there is not intense heat. It's the same stuff that's commonly used for a lot of household sealing tasks, so you can even get it in BIG TUBES for a CAULK GUN. The smaller size should be enough for a typical PDI. Do not apply silicone to the connections themselves, that's what the dielectric grease is for. Apply silicone to the outside of the connectors where the wires are open to air, to create a more watertight connection. You may also wish to put a bead of silicone around the joint of the two connector pieces to seal it there. This is especially useful for scooters ridden or stored in wet or damp environments.
Check all engine and frame grounds to ensure they are secure and making good contact. You may wish to apply dielectric grease to the ring terminal and the area it bolts to. Some prefer to remove frame grounds, clean the area, re-install the bolt with thread locker using proper torque, and paint over the newly installed frame ground to protect it from corrosion.
Remove each bulb and apply dielectric grease to it's base/connections and reinstall. Do not apply grease to the glass portion of the bulb. Avoiding handling the glass portion of bulbs with bare hands, especially headlight bulbs.
Many opt to replace the stock fuse holder. MINI-BLADE (ATM) STYLE and REGULAR BLADE (ATC) STYLE fuse holders are the most preferred choices for replacing the stock AGC fuse/holder. Some have an LED INDICATOR to alert you if a fuse is blown. Whichever style you choose, get an appropriate wire gauge (AWG). 14-16AWG should be fine for most. You can use larger (10-12AWG) if you'd like, but it may not match up to the existing wiring as easily. Check the amp rating as well. 10A is very common on small scooters, but a fuse holder with a higher rating is good as long as you use the appropriate fuse in it. Don't forget to get a fuse and spares of the appropriate rating and style to keep handy as well : MINI (ATM), REGULAR (ATC), GLASS TUBE (AGC).
Cut the old fuse holder out and solder the new one in place. You can use crimp-on connectors, but solder is the preferred method. Protect connections with HEAT SHRINK TUBING and/or electrical tape. Use the same amp rated fuse as the one you replace, which is generally around 10A for most small displacement scooters.
Check the operation of electrical systems before installing the body panels near the end of your PDI. You will need to install or temporarily install the battery to do this. The headlight and tail light and other running lights may not function without the engine running, since many scooters use AC power from the stator for those lights. Troubleshoot any issues before continuing the PDI process.
Ensure that all wires, hoses, cables, and essential components are secured in a matter that will not allow them to contact moving parts and to provide sufficient clearance from hot components such as the exhaust. Add CABLE TIES or other securing means where needed.
When installing the battery into the battery box, you may wish to find a way to secure it from moving if it is a loose fit. Vibration is not good for the battery, and the rattle some make can be annoying to the rider. It usually works best to install some form of dampening material in the floor of the box and around the battery. Ideally, the material should be chemical and heat resistant. You may be able to create a battery hold down using something as simple as a heavy duty zip tie. Whatever you do, don't use any conductive materials that are not totally secure and a safe distance from battery terminals.
If you'll be doing any wiring you'll probably need wire terminals, though solder may be used in place of some types of connectors. Most connectors will be color coded so you can quickly identify the size you need. Red is typically 16-22AWG, blue is usually 14-16AWG, and yellow is for 10-12AWG wire. CLICK HERE for more info on AWG sizes. They are more expensive, but TERMINALS WITH HEAT SHRINK are available that eliminate the need for heat shrink tubing or electrical tape to better secure them to wires.
-BUTT CONNECTORS are used to join two wires together if not soldering, such as when you connect an inline fuse holder.
-RING TERMINALS help you make connections to the frame or battery terminals. Ring terminals come in a variety of hole sizes to fit different studs so be sure to get an appropriate size (MORE INFO).
-QUICK DISCONNECTS may be needing if you're adding accessories to make connections to a switch or relay or if you need to join wires so they can be separated easily later. FEMALE QUICK DISCONNECTS are used for switch and relay terminal connections. MALE QUICK DISCONNECTS are primarily used in conjunction with female to join wires.
-BULLET CONNECTORS are an alternative to quick disconnects for wire joining that can be unhooked without cutting. These connectors are found on some scooters in stator, brake switch, and other wiring.
-WIRE SPLICES are used to tap/splice into an existing wire if not using solder.
An ASSORTMENT could be a cheaper way to get terminals or some hardware stores sell individual terminals so you can get only what you need.
Fuel, Vacuum, And Other Hoses
Fuel hoses are sometimes of poor quality. TYGON F-4040-A is a good choice for fuel hose if you want to be able to see fuel in your lines, which can be helpful for troubleshooting. You can also go to about any auto parts store and ask for fuel hose sold by the foot. The black rubber hose sold at auto parts stores is often a bit tougher with thicker walls, but of course you can't see through it. Whatever fuel hose you choose, make sure it matches the sizes of your petcock, fuel filter, and carburetor inlet (usually 3/16"-1/4"). 3/16" hose will often work a little better with stock barbs on small displacement scooters. 3ft of hose will do most scoots with a rear tank, but take a rough measurement with a tape if you are unsure and buy a little more than you think you'll need.
Replace the fuel filter with a clear filter so you can see it's condition as well. There are lots of options for fuel filters that fit scooter-sized fuel hoses. I suggest choosing something that allows you you see inside of if it, and many do. VISU-FILTERS are a popular choice as are mower and motorcycle inline filters. Select an appropriate size to match the rest of your fuel system. Be sure to note the direction of flow when installing a fuel filter. Look for an arrow on the filter indicating direction of flow.
Replace the stock clamps with heavier duty hose clamps. Do not tighten the clamps so much that you cut into the hose. Some use zip ties as fuel clamps. I do find zip ties acceptable for some fittings, such as vacuum lines, but prefer better clamps for fuel lines. A failed fuel connection could potentially cause a fire, so it seems logical to me to use good quality clamps for a few dollars extra. Worm gear clamps are the most popular choice when replacing the stock clamps. THESE 1/4"-5/8" CLAMPS cover most of what you'll do on a scooter because of their adjustability, although they are not small enough for most vacuum lines. FUEL INJECTION HOSE CLAMPS are designed to avoid cutting into hoses as worm gear clamps may if even slightly over-tightened. These SPRING CLAMPS are like what's stock on most scoots for fuel hoses, but a little stronger. THIS STYLE is similar, but with more clamping area. Spring clamps work in a more narrow size range.
I prefer to replace the vacuum operated fuel petcock with a manual fuel shutoff. A vacuum petcock relies on engine vacuum to allow fuel to flow and fill the carburetor. This means longer cranking times for the initial start and when doing jet changes. Vacuum petcocks are also more prone to failure. A manual shutoff is a simple valve installed in the fuel line that can be turned on or off manually. It makes priming the engine faster and they almost never malfunction. The downside is that if you don't manually turn the fuel to the carburetor off when you park your scooter, a carburetor float malfunction could lead to flooding and gas overflowing out of the carburetor onto the scooter and the ground in a worst case scenario until the tank is emptied.
The manual fuel shutoff should be placed inline, before the fuel filter. Pretty much any scooter can use an INLINE MANUAL SHUTOFF VALVE. They are available in various styles and sizes, but 3/16" and 1/4" are the most popular, just make sure what you use matches the size of the rest of the fuel system. Some scooters with petcocks threaded onto the tank may be able to use THREAD-ON SHUTOFF VALVES connected directly to the tank like the stock vacuum petcock. There are multiple thread sizes and you must know which yours is before buying anything to thread onto the tank.
There will be a vacuum line attached to the old vacuum petcock. You will need to trace that to it's origin (usually on the intake) and cap off the port after removing the hose.
Vacuum hoses should be replaced with quality vacuum hoses. Replace them one at a time. Worm gear hose clamps, spring clamps, or even cable ties are acceptable as long as they are secure.
The majority of 50-150cc Chinese scooters use 5/32" to 3/16" inside diameter vacuum hoses. Don't use just any hose that fits as a vacuum hose. Vacuum hoses are designed to handle vacuum while others may collapse. You can get SILICONE HOSE in a few colors for dressing up the engine and they tend to be more temperature and abrasion resistant than standard hoses. Unless designed for oil use, silicone hoses should not be used where there is oil so they may not be the best choice for PCV hose.
You may also want to replace vacuum tees, if your scooter uses them, with better quality PLASTIC or even BRASS TEES. You can also get Y FITTINGS. Make sure you get accessories that work with the hose size(s) you're using.
You'll need VACUUM CAPS if removing vacuum lines to cap off the barbs left behind. Again be sure they fit the size you need.
The carburetors on new 49cc four-stroke Chinese scooters are often "sealed". This means they have some or all of the following that need to be dealt with to allow adjustments:
-A plug blocking access to the mixture screw.
-Screws with snapped off heads securing the bowl.
-Soft or snapped off screws securing the carburetor top.
-A needle that does not allow for adjustment, because the clip can only be put in one groove.
The plug blocking access to the mixture screw can usually be removed with a screw extractor set. The set should include a series of numbered extractors and drill bits that correspond with each extractor. Mark the center of the plug with a punch or spring loaded center punch. Choose either a #1 or #2 extractor and drill bit. Put the drill bit that corresponds with the extractor you will use and drill into the plug that blocks the mixture screw. Go easy. You don't want to damage the mixture screw. You should be able to feel when you're through the plug and stop immediately, or you can stop before reaching the end of the plug sometimes. Remove the drill bit and replace it in the drill with the extractor. Put the drill in reverse and apply pressure as you drill into the hole you created with the drill. The plug should come out, allowing access to the idle mixture screw.
Some carburetors have a different style of tamper-resistant mixture screw. They may use a screw with no groove for a screwdriver or a D-shaped head. The plain-headed screw can usually be removed with small needle nose pliers. Then a slot can be cut into it with a hacksaw or small cutting blade to allow adjustment with a flat screwdriver. The D head should be adjusted with a special tool with a "single D" tip or bit. Some have made their own tools out of old sockets and other things.
The tamper-proof or tamper-resistant screws in that secure the bowl should also be removed with a screw extractor set, using the same procedure as described for removing the plug listed above. Once removed, most carbs can use M4x0.7x14mm machine screws and M4 lock washers to replace the extracted screws.
The carb top or cap may have soft or tamper-resistant screws securing it. Soft screws are very low quality screws that often strip before coming loose. Soft screws may be able to be removed with a tight fitting screwdriver, tapped into the screw with a rubber mallet, and pressure while unscrewing. You may be able to grab the soft screws with vice grips to remove them. Cutting a straight groove across the screw head will sometimes allow removal with a flathead screwdriver. Tamper-resistant screws and stubborn soft screws should be removed with a screw extractor set, using the same procedure as described for removing the plug listed above. Once removed, most carbs can use M4x0.7x10mm machine screws and M4 lock washers to replace the extracted screws.
Jet needles that have only one setting may be raised to enrich the part throttle mixture if necessary by installing 2.5mm or #4 washers under the needle clip. You could also try to find a replacement needle that has multiple grooves to allow for easy adjustment.
The easiest way to deal with a sealed carb is to replace it with a standard carburetor that is not sealed. Keihin PD18J and PD19J carburetors are a popular choice for good quality replacement carburetors for GY6 50 / 139QMB type four-stroke engines.
Hopefully your brand new carburetor won't be dirty, but if it is you'll probably want to use CARBURETOR CLEANER to clean it. If you have the carb apart it's not a bad idea to spray it out just in case.
Engine Checks And Procedures
Always check an owner's manual or service manual for the recommended spark plug, but I advise using a reputable brand such as NGK. Iridium plugs are more resistant to fouling and may provide easier starting.
Below are the most commonly used spark plugs for Chinese scooters.
139QMB / GY6 50 and GY6 125-150 : NGK CR7HS (STANDARD) or NGK CR7HIX (IRIDIUM)
1E40QMB / Minarelli / Jog Clone : NGK BR8HS (STANDARD) or NGK BR8HIX (IRIDIUM)
Even if you don't replace the spark plug, you may want to CHECK THE GAP. Most do well with 0.026"-0.028", but you should refer to a service manual for exact specs.
A small dab of ANTI-SEIZE can be used on the threads of the spark plug for easier removal later.
Stock Chinese spark plug boots are usually O.K., but not great. NGK spark plug boots are available that fit common Chinese scooters. I use an NGK VD05F for 139QMB and GY6 125-150 powered scooters and an NGK LB05EP for 1E40QMB Minarelli clones. They offer many more options with different angles and features that you can find more information about HERE.
The boot should unscrew from the end of the plug wire. If the end of the plug wire looks damaged you can cut off 1/4" or so. Once the old boot is removed the new boot can be screwed on snug.
Ensure that the plug wire is secured to the ignition coil and check the wiring connections to the coil if you didn't do so earlier in the PDI.
(Four-Stroke Only) The valve lash should be checked and adjusted if necessary. Refer to a service manual or other document for your specific engine. The PDI playlist linked earlier has a VIDEO of the procedure and there is a how-to with pictures HERE. Even if the clearance is good without adjustment, I would advise checking that the adjuster is secure. If you tighten the adjuster, re-check clearance to assure it did not change.
(Four-Stroke Only) Engine oil should be changed before the scooter is started. Some do take their first ride with the oil that comes in the engine. I don't trust shipping oil and I don't trust that the engine is filled properly. If you do decide to run the engine with the included oil, check the oil level before starting the engine and change it within the first 25 miles.
Motor oil for four-stroke Chinese scooters is usually listed as 10W40 to 15W40, while owners commonly report using anything from 10W30 to 20W50. There is a huge selection of oil available for four-stroke engines including standard (mineral/petroleum-based), semi-synthetic, and synthetic. SHELL ROTELLA T is a popular choice for a standard oil. ROYAL PURPLE is a common synthetic. I'm not an oil expert so I'll advise you to do further research if you wish to delve deeper into the characteristics and composition of motor oils. Whatever oil you choose, most advise to wait 500-1,000 miles or more before using synthetic, so start with a petroleum-based oil. Manuals for 139QMB and GY6 125-150cc engines normally declare somewhere between 600 to 900ml of oil. I use 750ml in these engines.
Change the oil frequently during the first 500 miles, then I prefer every 500 miles. Some perform and oil change every 1,000 miles instead.
Most Chinese scooters do not need to use a motorcycle specific motor oil. Those oils are designed for use with wet clutches, which most Chinese scooters do not have. Models that use clones of trailbike/xr50/pitbike engines do have wet clutches and do require motorcycle specific engine oil.
(Two-Stroke Only) At least, check the oil level in the reservoir. Check your owner's manual or a service manual for the location if you can't find it. You should check the reservoir regularly. Your two-stroke injects the oil from this reservoir into the carburetor or intake to lubricate the engine. Most 2T scooters do have a low oil warning light, but don't rely on it. Lack of oil will lead to engine seizing and failure very quickly. I prefer to replace the stock oil (if it comes with any) with a quality two-stroke oil. You should be able to remove a hose from the reservoir to let the oil drain. Refill with a two-stroke oil approved for injection systems. There are pre-mix and injection specific oils, and some that are fine for both. Check the label. For two-strokes I use a quality synthetic engine oil right from the start, but some prefer a non-synthetic for the first 500 miles or more. You may wish to bleed the system to ensure your engine gets oil at startup. You could also opt to remove the oil injection system and pre-mix your gas and oil instead. You can find more information about that HERE.
Gearbox (final drive transmission) oil should be changed before riding. Like engine oil, you can get PETROLEUM BASED and SYNTHETIC GEAR OIL. The price difference isn't much, especially since one quart of gear oil is enough for about seven changes in the typical scooter that requires 100-120ml. I've been much more pleased with the results using synthetic in my scooters, but everyone has an opinion on oils. The most common weights are 75W90 and 80W90. Either is fine. You may find recommendations to use 10W40 motor oil as gear oil. It sounds like you'd be using a much thinner oi, but 10W40 motor oil is actually similar to the viscosity of 75W90 gear oil. I suggest using gear oil, since it is specifically formulated for the demands of a gearbox.
Gear oil should be changed again within the first 500 miles, then every 1,000-2,000 miles.
Magnetic drain plugs are great for attracting magnetic metal particles so they don't circulate in your oil where they could damage/wear moving parts. You will need a kit specific to your engine such as THESE FOR 139QMB or THESE FOR GY6 125-150. If you have a two-stroke you should only have a gear oil drain plug. 1E40QMB/Minarelli/Jog clones use an M8x1.25 DRAIN PLUG for gear oil.
Exhaust header bolts or nuts, what secures the pipe to the cylinder or cylinder head, coming loose is a pretty common issue. Some scooters come with studs and others come with bolts. I prefer to use studs. Most 49cc and some 125-150cc Chinese scoots can use M6X1.0 STUDS. Some 125-150cc GY6s may use M8x1.25 STUDS. You'll need two studs. On each stud I use two NUTS of an appropriate thread size/pitch. If your scooter has studs stock, but uses long cap nuts I suggest just replacing each cap nut with two standard nuts. Install one nut and tighten it. Then install the second nut just finger tight. Use a wrench to hold the first nut in place while you tighten the second nut against it. This helps to lock the nuts together and I've had much less trouble with exhaust fasteners coming loose using this method. You may want or need to use a WASHER or LOCK WASHER between the first nut and the header.
You may wish to go around the engine check any fasteners not previously dealt with. Some choose to check the CVT over as well, particularly the nuts that hold on the variator and rear pulley/clutch assembly. There is more info on CVT inspection (though most of it is not needed for PDI purposes) in THIS VIDEO. When dealing with fasteners, especially small ones, be very mindful of torque values. You can consult a service manual and there is a table showing generalized torque specifications by fastener size later in this article.
Add fuel to the gas tank. If you've switched to a manual petcock with clear lines/filter you should be able to turn the petcock on and watch the lines and filter fill. If you are still using the vacuum petcock you will have to either crank the engine over or apply suction to the vacuum line leading to the carburetor to prime the system. Again watch for fuel to fill the lines and filter. Look the lines, tank, and carburetor over for leaks. If any leaks are found, fix them before attempting to start the engine.
Even if you opted to skip the oil change during the PDI, check the oil level and add oil if necessary before starting the scooter.
Look at the carburetor's throttle linkage. Make sure it is nearly closed with the idle speed screw allowing only up to 1/8" gap from fully closed. Turn the mixture screw inward, counting the amount of turns it takes to gently seat the screw where it stops moving. Rotate the mixture screw outward about 2 turns or you can go back to the original setting. Generally 1.5-2.5 turns out is a good starting point.
If you're working indoors, push the scooter outside or at very least open doors and windows for ventilation.
Once you've double checked everything, put the scooter on the center/main stand if it's not already on it. The scooter should not be started on the side/kick stand. The center stand is not only more secure, but it should also allow the rear wheel to be off of the ground. This eliminates the risk of the scooter shooting off out of your control in the event that the throttle is too far open.
Turn the ignition key and kill switch to the run position. Hold one or both brake levers and press the starter button. You should hear the engine cranking over. If you skipped priming the fuel system, it will need to crank over for a short period to fill the carburetor's bowl with fuel. Sometimes it is necessary to open the throttle slightly to get the engine to start.
Once the engine is started, adjust the idle speed screw if necessary so that RPM is high enough that the scooter doesn't stall yet not so high that the rear wheel spins rapidly. Allow the engine to warm up for at least 5 minutes. During this time you should monitor the scooter, check for leaks, strange noises, or anything out of the ordinary. Shut the engine off if you see or suspect that anything is wrong and investigate.
Once the engine is warm, again at least 5 minutes of running, adjust the idle mixture and speed screws. The speed should be set before beginning adjustment of the mixture screw. Just as described above, RPM should be low enough that the wheel isn't spinning quickly and high enough that the engine doesn't stall out or stumble. Turn the idle mixture screw 1/4 turn in either direction. I suggest starting by enriching the mixture.
If your scooter has the mixture screw on the inlet side of the carburetor, that's the side where the airbox attaches, the screw controls air for the idle circuit. Screwing it in cuts off more air for a richer mixture. Screwing it out allows more air past which causes a leaner mixture. If your carburetor has the mixture screw on the outlet side, the side the intake attaches to, the screw controls fuel. Screwing it in blocks the flow of fuel and causes a leaner mixture. Screwing it out allows more fuel to pass by and richens the mixture.
Give the engine at least a few seconds to settle after the mixture screw has been moved. If the idle speed increases or does not change, go another 1/4 turn in the same direction. If the idle speed decreases, turn the mixture screw 1/4 turn back to where it started and then another 1/4 turn in the opposite direction. Again let the idle settle after adjustment. If idle speed increases too much at any point, back the idle speed screw out to achieve a reasonable idle RPM once again. Continue this process, 1/4 turn at a time. You should find a point of highest RPM and beyond that RPM will drop. Set the mixture screw where idle RPM is highest and then an extra 1/8 turn toward rich. Your idle mixture is now set and you can adjust the idle RPM one last time.
If you find that the mixture screw must be all the way seated or very far out (to or near the point that the screw feels loose) for best idle, you may need to swap the pilot jet. If you have the screw all the way lean (screwed all the way in if on the outlet side or screwed way out if on the inlet side) consider a smaller pilot jet. If the screw is set about as rich as it can safely go (screwed way out if on the outlet side or screwed all the way in if on the inlet side) consider a larger pilot jet.
You may choose to take the first ride without every body panel installed, in case there is a need to service something on the road or after you return. If you ride without full assembly you should still have all essential components such as the seat, handlebars, floorboard, wheels, and so on properly installed and secured. Make sure no cables, hoses, or wires are near any moving parts. Never ride without the cooling fan and shrouds in place. All lights should work including the headlight, tail/brake light, and turn signals.
Warm the engine up before taking your first ride. Do a pre-ride safety inspection while it warms up. Check tire pressures, ensure all lights work, adjust the mirrors, and verify that the brakes stop the scooter before you get out onto the roadway.
There are two common engine break-in methods, easy and hard. Decide which you prefer before riding for the first time. Easy and hard do not describe the difficulty of these methods, but rather if you are "easy" or "hard" on the engine. Easy break-in involves being gentle on acceleration and limiting speeds for some amount of mileage. Hard break-in allows heavy throttle on even the first ride. I can't tell you for sure which is the best. I can tell you that I use a hard break-in method on all of my scooters and I advocate doing research to decide for yourself. MOTOMAN'S SITE is probably the most famous hard break-in page.
What I do on the first ride begins by varying RPM. I don't like to keep engine speed constant during break-in. No cruising at a steady speed and steady throttle position for me. Even if you don't have a tachometer to display RPM you can listen to the tone of the engine to tell that RPM is changing. I do basically what is described in MotoMan's method previously linked. I apply 1/2 throttle for a short burst and let it decelerate for a few seconds. I do that a few times. Then I apply 2/3-3/4 throttle and slow the same way a few times. Then I give it everything (WOT) a few times and again let it decelerate each time. I continue to vary RPM for at least the first 20 miles. Some would argue that break-in goes for very many miles. Again, do your research and decide for yourself.
If you will be speeding up and slowing down as I do, don't do it on the road in front of traffic. Find a road with little traffic like perhaps a back road an industrial park or even large parking lot. If you're new to riding an empty parking lot may be the safest place to start your scootering experience regardless of break-in method. New riders should make themselves comfortable with all controls, starting, stopping, and steering, before ever entering a public roadway IMO. There are some PRACTICE IDEAS HERE that new riders may find useful.
Allow the engine to cool down after the first ride. Once it's cool, recheck fasteners and tighten if necessary. Exhausts nuts/bolts are notorious for coming loose within the first rides. I advise not only checking the fasteners after the first ride, but again around 500 miles or so. I also prefer to change both the gear and engine oils after the first ride or at least within the first 100 miles.
Check out THIS LINK to a take-along tool kit. Some of the smaller items aren't ideal for everyday use, but may be an option for infrequent use to save on buying two sets of tools.
|Item||Links And Notes|
|Basic Tool Kit|
This should be reasonably self explanatory for even beginners. Screwdrivers, sockets, ratchets, wrenches, a hammer, and hex keys. The basic tools required to do about any job. You can buy these items individually, but it may be cheaper to purchase a kit. Many kits also include an organized carrying case that makes it easy to spot if anything is missing. Most scooters use metric fasteners, so be sure whatever you choose has metric wrenches and sockets. Bottom of the barrel cheap tool sets may be less ergonomic and not constructed well. These are tools that will come in handy regularly for future scooter repair and maintenance.
HERE is a 170 piece tool kit that appears to cover the basics other than a hammer.
Please note that just because a hammer is considered a basic tool, you should not make a habit of beating on parts. Sometimes a hammer is needed though. Consider a DEADBLOW HAMMER for general scooter use. The coating can provide some protection for surfaces when tapping on them.
|Large Adjustable Wrench And/Or Pliers|
If the steering stem nuts are loose, you may need wrenches or pliers larger than what a ready made toolkit will provide. Sometimes there are two nuts that need to be locked together, so you would need 2 tools capable of this. In that case I would suggest one LARGE ADJUSTABLE WRENCH and one pair of LARGE TONGUE AND GROOVE PLIERS. That way you have two different tools for various tasks. The adjustable wrench can be used for clutch assembly nut removal as well, using the technique shown HERE. Some clutch nuts are over 1.5" so keep that in mind and take note of the tool's capacity.
If you swap out the valve stems as shown in my PDI videos, you'll need a C-CLAMP to hold the tire out of your way and possibly to break the bead of the tire. They come in various sizes so be sure to get one that opens wide enough to accommodate your wheel/tire. A 6" model as linked should cover most scooters.
|Valve Stem Core Tool|
You need a VALVE CORE TOOL to remove the core and release all of the air from a tire and to reinstall the core before refilling the tire. All shown in the PDI video series. You can get them as SCREWDRIVERS if you prefer and even built into VALVE STEM CAPS. I'm not sure that the caps are a great idea unless your scooter is parked in a secure area. I know a mischievous person could let the air out or slash them, but do you want to give them a tool to flatten your tire and take the core within 10-20 seconds?
|Tire Pressure Gauge|
I believe everyone that owns a scooter should own a tire pressure gauge. They are not expensive and they help help to ensure safe riding, proper tire wear, and proper fuel economy. I would suggest a DIGITAL TIRE PRESSURE gauge. They're easy to use/read and many are proven to be very accurate. You can also get STICK and DIAL types.
For doing tire service at home you will need an air source. The cheap way may be going to a local service station and using their coin-op air compressor or perhaps a mechanic shop would do it at no to low cost. That's obviously not doing the job all on your own at home though. A BICYCLE PUMP should work, but I'd have to imagine you're in for quite a workout going that route and the tires won't be filled quickly. I think a better option for most will be an electric tire pump. A 12V TIRE PUMP can be used with the scooter's battery or a car battery so you can inflate tires anywhere you go. You can also get small affordable ELECTRIC PUMPS that work on household current. One issue with the pumps (bike or electric) is that they are not going to be able to seat a tire. Seating a tire requires a much larger volume of air, so consider the following options for that purpose. You can get an AIR TANK to hold compressed air. A tank won't produce compressed air to fill your tires, but you can take it to a service station or maybe even to a friend with a large air compressor to have it filled. If you'll be running air tools, such as pneumatic impact wrench as covered later, you will need a much more serious AIR COMPRESSOR AND TANK COMBO as well as accessories such as fittings, hose, and a TIRE INFLATOR. There's a lot to consider when buying a whole setup like that, so read about compressors and accessories before making that leap.
There are many potential uses for feeler gauges. For PDI purposes they are used to check/set valve clearance on four-stroke engines. Not all feeler gauge sets include the same sizes. THIS SET starts at 0.0015" so it covers down to the lowest setting most engines would need.
|Spark Plug Gapper|
COIN STYLE spark plug gap tools are the most common. You can usually find a stack of them on the counter of auto parts stores. They can be hazardous to iridium plugs, because users have a tendency to pry between the electrode and ground strap with them and exert more force when checking gap. Coin style gauges can set iridium plugs safely when proper technique and caution is used. THIS STYLE may be a better choice, but it offers limited settings unless you can find a specialty model. The one linked has 0.025" and then .0030". There's no accurate way to try 0.027" for example if you are experimenting with gaps or following exact specs. A set of spark plug FEELER GAUGES should have more precise steps, but you'll need another tool to open the gap.
|Spark Plug Socket|
Your scooter may include a spark plug wrench, but a SPARK PLUG SOCKET may be easier to work with since you can use it with various configurations of ratchets, extensions, and swivels. Spark plug sockets are also made to hold the plug so installation and removal is easier. There are two very common sizes in small Chinese scooters. 5/8" (139QMB, GY6 125-50) and 13/16" (1E40QMB).
It's not necessary for the average PDI, but if you'll be looking at the stator or checking seals behind the flywheel you will need a way to remove the flywheel first. Some use a HARMONIC BALANCER/STEERING WHEEL PULLER for this, but a purpose-built flywheel puller is a better choice in my opinion. They tend to do the job faster and easier at a similar cost. You may also need to buy bolts for the steering wheel puller that fit your flywheel (likely M6x1.0, but check first). If you go with a flywheel puller, you have to get one with the appropriate thread size, pitch, and direction to fit your flywheel. 1E40QMB two-strokes and GY6 125-150cc engines should use an M27x1.0 LH PULLER. 139QMB engines use an M24x1.0 RH PULLER.
If you plan to inspect the clutch, variator, or behind the flywheel without an impact wrench (see below), you'll have to find a way to keep the crankshaft or clutch from moving while you loosen and tighten the nut. An ADJUSTABLE PIN SPANNER WRENCH can handle those tasks in most cases. There are a lot of HOMEMADE VERSIONS as well. GY6 125-150 engines make great use of that holding tool, while others will require you to remove the fan shroud and fan to hold the flywheel on the opposite side as you remove the variator nut. Some popular scooter engines have variator tools made specifically for them such as THIS ONE for the 139QMB/GY6 50 or THIS ONE for the Minarelli clone 1E40QMB.
An impact wrench is great for CVT work and removing the axle nut that holds the rear wheel on. These tasks can be accomplished by other means, but an impact wrench is the quick way to do it. There are pneumatic (air) and electric models. Pneumatic powered impact wrenches require an AIR COMPRESSOR, fittings, and hose. Great tools to have for an enthusiast, but probably not worth the investment for someone looking to do only the PDI and routine maintenance unless you already have a compressor setup. There are lots of things to consider before buying an air compressor if you get into that, more than I want to get into here. Electric impacts can be bought to use with 110V AC (household) and 12VDC (car/scooter battery) as well as cordless models. An electric impact wrench that is corded for use with household current or 12VDC will likely be the most cost effective and is fine for scooter repair. As with anything, there are different quality levels and power levels. Impact wrenches again come in different drive sizes and generally larger models have more power, but check the torque specs if possible.
12VDC ELECTRIC IMPACT WRENCH
110V ELECTRIC IMPACT WRENCH
18V CORDLESS IMPACT WRENCH
PNEUMATIC IMPACT WRENCH
Some impacts have A LOT of power. Plenty to snap off large bolts and studs. You must use caution with an impact wrench when installing fasteners. Never begin threading a nut or bolt in/on with an impact. Start them by hand and only use the impact wrench once you are certain the threads are properly engaged and not cross-threading. You may want to use torque limiting devices for some torque wrenches, commonly called torque sticks, to lessen the risk of ruining threads or fasteners. They come in different ratings, for example 50ft-lb, 60ft-lb, etc... Choose ratings based on what your scooter's fasteners require.
Also be sure to use impact sockets with impact wrenches. They have thicker walls than standard sockets to better withstand the force of impact use.
1/2" DRIVE METRIC IMPACT SOCKETS
A torque wrench is not essential for most PDIs. One should be used if dealing with certain engine fasteners, such as cylinder stud nuts. If you are new to wrenching, consider using a torque wrench at first to get an idea of how much force you are applying to fasteners. Quality torque wrenches can be quite expensive. Consider borrowing one from a friend if possible since it's not a daily use item for most. There are multiple styles of torque wrenches, such as beam, click and electronic. I would suggest doing farther research before buying to decide what suits your needs and budget the best.
Torque wrenches come in many ratings. Make sure you choose one (or more) that covers the range you need. For example, don't buy a torque wrench that only goes to 25ft-lbs if you plan to torque something to 40ft-lbs. You may find a deal on a torque wrench rated with in-lbs. Convert from in-lbs to ft-lbs by dividing by 12 (ft-lbs = in-lbs / 12). Convert from ft-lbs to in-lbs by multiplying by 12 (in-lbs = ft-lbs x 12).
Also note that they come in sizes such as 1/4", 3/8", and 1/2" drive. This denotes the size of sockets that the wrench is compatible with. So if you have a 3/8" drive torque wrench it should be used with 3/8" drive sockets. 1/4" and 3/8" are the most common choices for scooter needs. Larger drives generally support greater torque.
Here are a few examples of torque wrenches :
CLICK TYPE 15-80FT-LB 3/8" DRIVE
BEAM TYPE 0-600IN/LB (0-50FT-LB) 3/8" DRIVE
ELECTRONIC 2-20FT/LB 1/4" DRIVE
|Thread Cleaning And Repair|
You will need either a THREAD CHASER SET, TAP AND DIE SET, or THREAD FILES to clean up damaged threads. Taps and dies can clean threads, but they are meant for cutting new threads. They're very sharp and it's easier to cross-thread using them. Thread chasers are my choice for thread cleaning. They're kind of like taps and dies, but not so sharp and easier to use. Thread files will do the job for bolts, but not nuts. You could opt to buy only the most commonly used thread sizes for chasers or taps and dies and try to save money that way. It depends on the scooter, but for Chinese scooters the most common size tends to be M6x1.0 and the next in line is usually M8x1.25.
A SCREW EXTRACTOR SET should be used for gaining access to sealed carburetors found on some scooters. The process is covered in detail HERE.
|Single D Driver||Some carburetors use a SINGLE D style idle mixture screw to aid in tamper proofing.|
|Oil Drain Pan|
You've got to put that old oil and gear oil somewhere. The floor and the ground aren't good options. The traditional approach is a catch can made by cutting up an old milk jug or coffee can. You can buy OIL DRAIN PANS, but they're usually intended for automotive use and don't fit well under some scoots without raising the scooter. I prefer using PLASTIC GRADUATED BEAKERS for my oil. I use them to drain and fill, that way I can see exactly how much oil goes in and comes out. You'll need 1000ml to hold the oil for most small 4T engines with a little room to spare.
In the long run it's cheaper to buy a funnel or FUNNEL SET than to use supplies cleaning up spilled oil. It's also easier to keep track of how much oil is added without needing to figure out how much is on the ground.
|Wire Cutting, Stripping, And Crimping|
If you will be working on wiring during your PDI you should have tools around to do cutting, stripping, and crimping. The cheap solution is an ALL-IN-ONE CRIMPER/STRIPPER/CUTTER. That's a decent quality all in one unit. You can get even cheaper ones as part of a KIT that contains the tool and a selection of terminals. Those are often a little tougher on your hands, don't always do a good job for as long, and the terminals may or may not be good quality but could be an option if you do minimal wiring. If you have aspirations of re-wiring the whole scooter or installing a lot of electrical accessories you can consider separate WIRE CUTTERS, SELF-ADJUSTING STRIPPERS, and CRIMPING PLIERS.
|Soldering Gun Or Iron|
If you will be using crimp-on terminals for your wiring, or not doing wiring, you can skip this. If you will be soldering, you'll need a SOLDERING IRON or SOLDERING GUN. A soldering gun looks like a gun. It heats and cools quickly as the trigger is pulled and released. Soldering guns are often used for larger jobs. A soldering iron is a pencil shaped tool that heats and cools more slowly, but remains hot as long as it's plugged in and turned on. You can get irons in different wattages and even ADJUSTABLE SOLDERING IRONS, but a simple model LIKE THIS will handle most scooter wiring needs. Don't forget to pick up some solder as well. There are multiple types and sizes, but something like this ROSIN CORE SOLDER should work.
Your new battery should have enough charge from the electrolyte activating to get you going and then a properly functioning scooter charging system will charge it while the scooter is running. Most prefer to charge the battery to 100% before ever using it though. I think this is the best way to do it. You'll need a battery charger that provides no more than 1.5 amps. I recommend the 12V BATTERY TENDER JR. It can be left plugged in anytime your scooter is parked because it is a float charger, so it stops charging on it's own to prevent overcharging. It's got LED indicators so you can quickly see the state of the charge and it includes quick disconnects that you can install on your scooter to make connecting it quick and easy.
You will need to refer to a service manual for torque specifications for your make and model of scooter and each fastener, but here are general specifications by fastener size. If you are dealing with the engine, always go by torque specs for the specific fastener and not general specifications. These are the actual thread diameter, not the size of the hex head on a bolt. For example, an M6/6mm bolt may need a 10mm socket or wrench to turn it, but the bolt's actual thread size is 6mm diameter.
I hope that you have found this article and the PDI video series helpful. I wish you the best of luck with your Chinese scooter experience and if you have questions along the way, post on the forum and we will do our best to help you. If you have suggestions for further improving this PDI article, feel free send them to me 90GTVert for consideration.
Thank you for reading!