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Post by Sir Scoots-A-Lot on Oct 4, 2018 14:57:30 GMT -5
The description leads me to think the enrichment system is not working at all. Everything done to get it to start will cause a richer mix. Hand over intake, twisting the throttle to work the accelerator pump & squirt in some fuel, etc. I would check that the enrichment passages are clean and the 'needle' retracted when the electric gizmo is cold. tom Thanks for ahe reply Tom. I agree there very well could be something wrong with the enrichment. I think it does something because the idle speer does seem to change on its own from whwn the engine is cold to when it is warmed up but it is a bit erratic. I think cleaning it is a great idea because even the tiniest bit of debris or build up would cause large effects on these tiny passages. I have never been inside a carb yet but just got my 88 91 and 94 main jets to go with my BBK...so sometime after my 40 mile roundtrip tomorrow morning I will be tearing my engine and carb apart to install the new parts and will make sure it's clean and put together to the best of my abilities. I will also check and clean maybe change my fuel filter as last time it had some weird funky gunk halfway blocking the filter a couple thousand miles ago
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Post by Sir Scoots-A-Lot on Oct 4, 2018 15:04:04 GMT -5
the new 47mm BBK with hardware, sliders and new main jets anxious to install into my scooter this weekend!!!! A picture of my spark plug a thousand or two K miles ago when I was having similar starting issues. I have not replaced this spark plug the entire time I have owned this scooter somewhere between 7,000 and 10,000 miles. The scooter had around 4500miles on its odometer when I purchased it and who knows ifi the previous owner ever replaced the plug either
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Post by Sir Scoots-A-Lot on Oct 5, 2018 22:51:30 GMT -5
The description leads me to think the enrichment system is not working at all. Everything done to get it to start will cause a richer mix. Hand over intake, twisting the throttle to work the accelerator pump & squirt in some fuel, etc. I would check that the enrichment passages are clean and the 'needle' retracted when the electric gizmo is cold. tom I went thru my carb, requiring vise grips to break the screws free, and what i found looked pretty clean. A few little black spots under the rubber thing thats attached to the needle jet. The needle jet clip was in the middle of 5 positions so I moved it one richer. In the bottom of the bowl it looked like maybe a tiny bit of very fine gold metal flakes maybe from brass or gold colered hardware--whatever it was it looked shiny but wasnt very much so I cleaned that out. The enrichment needle looks to be all the way out not extended at all as intednded when i took it off although it seems like with the cresent washer that holds it down it needs to be seated a certain way otherwise it could sit a bit lower or higher to start with. I think I put that back on properly. When I disconnected the enricher power plug I noticed the connection seemed a little loose like instead of the electrical connection inside plugginfg in and the pins fitting tight it seemed like the outer plastic connector clips was holding it together a couple mm away from being plugged all the way in so i will try to bend the plug pins a hair to get better electrical contact, plug it all the way in and tape it together all the way in to help ensure it is working properly. I don't know how else I could test the enricher.?? main and idle jets appeared clean but i cleaned them with fine wire and air just in case there was film. I installed a #94 main jet in preperation of adding the 47mm cylinder and piston this weekend. I hope to try starting the scooter before installing the kit to see if I fixed any possible air/fuel issues first. I am thinking maybe I need a valve adjustment also as it has probably been over 1,000 miles since i adjusted them and I'm not overly confident I made the valve lock nuts as tight as I could have. Other than that I will also be checking cleaning and maybe replacing my fuel filter and replacing my fuel lines I got from Autozone that have maybe 5,000 miles on them and 4.5 months as I was quite surprised to find parts of the lines worn and other parts hardening. I think it is possible one or more of the very tiny air and fuel passages could also be partially clogged as there are many passages, I cleaned what I could but I couldnt get wire thru all of it nor air fitted to some tiny passages. So I will also be running carb cleaner thru it. I heard from some people that the ethanol gas is especially bad for small engines with so many small passages as the ethanol can leave an extra filmy build up that regular gas wouldn't--not sure if that's true or not but many claim it to be so and I think where I live all the gas is at least 15% ethanol or something although I haven't paid much attention to that-yet
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Post by Sir Scoots-A-Lot on Oct 7, 2018 15:29:58 GMT -5
I keep thinking I have my trouble starting figured out. right now I am fairly confident my scoot starts at about the lowest acceptable idle speed and at 3.5 turns out of the a/f mix screw with the engine maybe 1/4 warm. I want to let it cool and retry starting. I hear people saying you shouldn't go much past 2.5 full turns out maybe becuase it starts being an issue of the screw falling out or not being far enough in to make a gasket seal with the o-ring or both reasons as I know those 2 problems both arise eventually when turning the a/f mix screw far out. So...I have put off installing my 72cc kit all weekend until I figure out the starting issue and I think I got it this time. I was close to solving it last week when my a/f mix screw fell out from being too far turned out. The solution must be to go to a larger idle jet. I currently have a claimed but un-numbered #32 jet in a 19mm carb with a highly non-restrictive reverse cone metal mesh air filter and I'm at sea level---all of which I understand would be cause to demand on the richer side of carb jetting. My solution is to order a #35 and #38, maybe even a 40 or #42 also for when I install the big bore kit if I ever get around to finishing it. I have it all setup and even had my valve cover off before deciding I needed to ru nto the store and have urgent paperwork to finish where I can't take a 1-3 hour break and be without transportion at least 12, maybe 24 hours while waiting for the gasket maker to seal properly as insurance on the provided gaskets that came with the kit. I have heard most people say #35 for BBK or even #32 for some work and heard of people trying #40 with mixed results--some saying #40 idle jet is a little big for the 72cc kit but if my kit is as demanding as the stock setup with my air filter mods then I expect a 38-42 should be the correct range. I feel as though even with my filter and sea level elevation that my scoot is demanding the idle to be a bit rich. I am definitley checking my valve clearance soon and wish i had a compression gauge as I'm guessing leak in compression somewhere could make my scoot demand a richer idle?? Thanks again everyone for the help. At this point I'm pretty much continuing to post in case anyone else has similar problems they can maybe learn something (at least some of what not to do...lol...like seriously dont turn the a/f screw out too far! I say anything over 3 full turns out is getting into sketchy territory for being loose enough to fall out, especially if your a/f mix screw doesn't have a spring holding it in place and even if it has a spring--at over 3.5 full turns out the screw no longer has a lot of itself threaded into the carb to counter the pressure from it's spring which could cause the screw or carb threads to get stripped and/or cross threaded if adjusted again and/or fall out somewhere probably getting at least the tiny parts of it lost forever on the road and maybe stranding you away from where you want to be.
after trying adjusting the idle and a/f mix many times it seems my scooter likes to start most of the time with the a/f screw 4.5 turns out, but still sometimes it takes a couple times and often I need to turn the idle all the way down while starting then back up after it starts. I now have #35 and #38 idle jets in the mail that will hopefully solve my issues , but if it doesn't then I'm starting to wonder maybe I have another issue somewhere such as vacuum leak and/or possibly my engine is a bit worn out at a roughly estimated 15-20,000 miles
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ratdog
Scoot Enthusiast
Posts: 342
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Post by ratdog on Oct 7, 2018 20:02:08 GMT -5
The carb has to work over a wide range of RPM. To do this you have different parts of the carb controlling different parts of the throttle setting. Of course your polit jet and mixture adjustment effect idle and just off idle. After that the main jet takes over. Of course at low throttle openings, you don’t need all the fuel the main jet can dump in. This is where the needle comes in. The needle slides inside the main jet, and has a taper. So let’s say at 1/8 throttle, the needle is deep into the main jet and the dia of the needle is fairly large, so it limits the fuel coming in from the main jet. Now we go up to 1/4 throttle, the needle is only part way into the main jet, so it’s dia is much smaller and more fuel cam flow into the carb. By the time you get to about 1/2 throttle, the needle no longer effects the flow from the main jet.
That’s all a very long way of saying that the needle only effects the mixture at lower throdle openings. But it also explains if you are getting a lean surge, raising the needle may help that.
Now to complicate the issue.
Years ago we had a cable connected directly to the slide/needle and when we opened the throttle, we were pulling up the slide. But they “fixed” that. Now the slide/needle is pulled up by vacume. Er are connected to a butterfly valve and as we open that, more vacume is created above the diaphragm, and that opens the slide. So it is ultra critical that the chamber on the top of the carb is air tight and that the slide does not bind inside the carb, and of course, make sure there is no leaks in the diaphragm. You may know all this, but because you asked about the needle, I thought I’d give you a little primer.
On problem that can happen with these CVT carbs is if the slide is. A little sloppy, it shakes around inside the cab and starts to bind.
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Post by Sir Scoots-A-Lot on Oct 8, 2018 12:23:28 GMT -5
The carb has to work over a wide range of RPM. To do this you have different parts of the carb controlling different parts of the throttle setting. Of course your polit jet and mixture adjustment effect idle and just off idle. After that the main jet takes over. Of course at low throttle openings, you don’t need all the fuel the main jet can dump in. This is where the needle comes in. The needle slides inside the main jet, and has a taper. So let’s say at 1/8 throttle, the needle is deep into the main jet and the dia of the needle is fairly large, so it limits the fuel coming in from the main jet. Now we go up to 1/4 throttle, the needle is only part way into the main jet, so it’s dia is much smaller and more fuel cam flow into the carb. By the time you get to about 1/2 throttle, the needle no longer effects the flow from the main jet. That’s all a very long way of saying that the needle only effects the mixture at lower throdle openings. But it also explains if you are getting a lean surge, raising the needle may help that. Now to complicate the issue. Years ago we had a cable connected directly to the slide/needle and when we opened the throttle, we were pulling up the slide. But they “fixed” that. Now the slide/needle is pulled up by vacume. Er are connected to a butterfly valve and as we open that, more vacume is created above the diaphragm, and that opens the slide. So it is ultra critical that the chamber on the top of the carb is air tight and that the slide does not bind inside the carb, and of course, make sure there is no leaks in the diaphragm. You may know all this, but because you asked about the needle, I thought I’d give you a little primer. On problem that can happen with these CVT carbs is if the slide is. A little sloppy, it shakes around inside the cab and starts to bind. I appreciate the info Ratdog. i agree the way they "fixed" these CV carbs should be in quatation marks because to me they seem more complicated. I have also been reading more about the carb the last 2 days and came across some similar info to what you said. I never knew how much everything affects idle. what I saw says the main jet and neddle jet and needle with the slide and diaprhragm all kinda work as one unit, although you can change or adjust the various parts and effect the throttle some all the way down to at least 1/8 throttle. I put in a 94 main jet because I WAS goi ng to put in a 47mm cylinder/piston but got delayed on that--the 94 jet plus putting the needle clip one notch rich of middle out of 5 nothces and turning hte a/f screw between 3.5-4.5 turns out now seems to do the trick starting quickly usually first try or first couple tries with my cone filter left on wheras before I would take the filter off and flood the engine before starting and try to put my hand over the carb air inlet to start it...so it seems like either the bigger main jet and/or needle position has helped with starting although now it feels like my scooter bogs down at any throttle position above 1/4-1/2 or so. I need to either rejet the main lower or get that new cylinder on asap. I also have 3 or 4 different larger pilot jets coming in the mail this week! So with everyone's help on here, especially Ratdog with carb tuning advice, and a shout out thanks to kagetenshi for verifying the carb jet thread size so I was able to order the proper size right away, and thanks Grumpyunk for your input, plus my own research and trial and error I think all this adjusting will fix the start problem....OR I have another issue like my current engine is worn out and hass compression loss, or needs valve adjustment or has a scored up cylinder or warped/worn piston/rings It can be a little frustrating at times, but I am a newb at this, still learning a lot and whenever I have the extra time and don't have somewhere I need to be fast, then tuning is a hobby to me. it's fun and Ireally appreciate having a community of people online to help me and share info with
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ratdog
Scoot Enthusiast
Posts: 342
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Post by ratdog on Oct 8, 2018 19:29:44 GMT -5
I may have asked this before (sometimes I confuse threads) but are you currently using a modified ignition? I know a lot of people have read on the internet about slowing the ignition pickup to get more advance, and many more are using an aftermarket ECU. The reason I ask is because this starting problem sounds so much like a too advanced ignition. Of course that is the issue with all the aftermarket ecu I have tested. This is one of those “if I only had it in front of me” times. 5 min and a timing light and I would have “time I guess” checked off the list. I have to be honest, I have never seen or heard of an engine so sentive to the mixture adjustment. That said, I think you are doing the right thing to get a larger polit jet. Something you might think of picking up, a numbered wire drill set. I see them on amazon including a pin vice ( to hold the drills). You would only want to try this if you had two jets (you can’t drill a jet smaller) Among other things you would be able to find out if the jets you have ar the size they are marked. I have had jets from different makers that show the size, but are really different sizes. 21-PC Mini Drill Set Numbered 61-80 Jewelers Bit Index Pin Vise Chuck Aluminum www.amazon.com/dp/B07BXPQC7H/?&ref=flgs_it_share
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Post by Sir Scoots-A-Lot on Oct 9, 2018 0:17:37 GMT -5
I may have asked this before (sometimes I confuse threads) but are you currently using a modified ignition? I know a lot of people have read on the internet about slowing the ignition pickup to get more advance, and many more are using an aftermarket ECU. The reason I ask is because this starting problem sounds so much like a too advanced ignition. Of course that is the issue with all the aftermarket ecu I have tested. This is one of those “if I only had it in front of me” times. 5 min and a timing light and I would have “time I guess” checked off the list. I have to be honest, I have never seen or heard of an engine so sentive to the mixture adjustment. That said, I think you are doing the right thing to get a larger polit jet. Something you might think of picking up, a numbered wire drill set. I see them on amazon including a pin vice ( to hold the drills). You would only want to try this if you had two jets (you can’t drill a jet smaller) Among other things you would be able to find out if the jets you have ar the size they are marked. I have had jets from different makers that show the size, but are really different sizes. 21-PC Mini Drill Set Numbered 61-80 Jewelers Bit Index Pin Vise Chuck Aluminum www.amazon.com/dp/B07BXPQC7H/?&ref=flgs_it_sharewow I wish i knew the drill set was so cheap. if I had taken the time to fully "unlock" the old carb I have then I could have just bought the drill set I suppose as I wouldve had an extra main and idle without ordering. The old carb started if I held the throttle to WOT for about 30-60 seconds before attempting to electric start and often kick started easier than electric. my battery is always about fully charged and cranks well. Perhaps I will buy the drill set if I have any more trouble. As it stands now I have 4 main jets -- an unmarked 85, and marked 88,91,94. One pilot supposed #32 but unmarked. I also have more numbered jets in the mail arriving in a couple days pilot #s 35 39 42 and a main 99 just in case for my BBK install if I ever find the extra hours of daylight I dont need to use my scoot during to clear my schedule and get it done. All the numbered main jets have a "K" stamp like the Keihin mark before the number and I ordered them from PartsForScooters.com which seems like a good store with a ton of parts on hand. I hope the pilot jet will solve it, Plus I have the main and idle jets, whatever sizes they are, that are still locked in the carb that came with my scooter As far as the ignition thing...I have not changed timing or CDI myself... I have no idea what the previous owner did. When I showed up to buy my scooter from an internet personals ad it looked like the guy was running a scooter chop shop or had a group of enthusiasts with some of his friends all working on nearly a dozen scoots in his driveway. My scooter has a lot of different brand parts on it. It looks like a 2 stroke 140qmb frame with Yamati Eurostrada plastics and a 4 stroke TAO TAO stamped 139qmb engine on it, It also has a Tomos CVT cover and the rear fender with plates and light fixtures says vento stamped in tiny letters. I don't have a timing light. I did check for spark and it came up ok, possibly slightly weak although I wouldn't know if its weak from experience. I want to get a cheaap decent copper spark plug when i get a chance and I suppose I could look into CDI if the jet doesn't solve it. I do have a problem that has come up more recenly where the battery connection isnt so great because I cheaply rigged together an oversized battery with oversized clamps for the wires coming off the scoot. they were connected fine for a couple months but now come lose intermittently as I can see the dash clock light flicker or the clock completely go off at times and sometimes it is very touchy an happens when I barely move the scoot. I fixed it some 2 days ago but after riding Monday, yesterday now, I parked it in my garage and I went to look at the start problem and the battery had come loose on my 8 mile ride. During my ride it took about 3 tries to start it when I left and only 2 tries on the way back after I parked it for 1/2 hr after riding 4 miles. I have heard of some scooters often taking 3 tries to start whereas others seem to start first try instantly about every time. I think part of my problem is that I sometimes get it tuned close to where it should be for starting but probably not right where it should be. Having an aftermarket free flow filter that I think flows more than a UNI filter probably doesnt help and I may investigate that. I also wonder if running this filter has possibly gotten some small debris in it over thousands of miles and added wear to the cylinder. Someone was warning me about that. I even ran it for at least a few hundred miles without a filter. I am hoping my engine isn't developing something along the lines of a soft seizing condition that I hear can be common among 2 strokes
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Post by Sir Scoots-A-Lot on Oct 9, 2018 20:47:51 GMT -5
went to start it today with no luck after having really good luck starting it yeasterday twice on an 8 mile roundtrip.
I tried starting it today for over 30 mins at dawn, probably annoying the heck out of neighbors and definitley annoying myself. WHat I know is yesterday it started twice within a 60 and 30 seconds on 3 and 2 tries with #32 idle, #94 main jets. After it started it would stumble on acceleration and not respond at all, cutting out at high throttle or high speed so every time I tried high speed/throttle and the power cut out i backed off quickly so it wouldn't stall and completed my trip at about 20-25mph. I was assuming it ws just the scoot bogging down with too big a main jet
When trying to start today I noticed the battery cables were loose somewhere and if i shook the bike a little the power would turn off, clock going blank and i had to move the connection s to get it back on, didnt take the time to fix the root problem ttoday. That being said when the power was on it seemed to crank fine, the cranking even sped up at times and made different noises as if it was about to start combustion, I also heard a few backfire like pops and I saw my first ever backfire--not exactly flames like something on fire burning but a red orange quick flash coming out of the carb with the filter off 2-4 inches long---Im guessing that means i was still getting spark as I didnt check that,
Things on my list to go over include---
Checking/adjusting valve settings.
Checking my oil level--I checked oi; a couple hundred miles ago and it appeared fine slightly on the high side mobil 1 10-30 done within last 500-1k miles/1.5 months.
Down jetting the main jet to maybe the #85 I have to see if that helps. The #94 I have on now seems like it could be causing too rich problems at any significant throttle positon so I THINK it needs to be lowered until I install the bigger cylinder kit. I say I think it must be bogging down from too much fuel because one other theory I have is that possibly my engine, maybe the cylinder walls and/or piston/rings are worn or warped from the current very roughly estimated nearly 20k miles on the not working odometer and hanging up in a partial "soft seize". If it is worn out hopefully my BBK could fix that..I am holding hope that it isnt worn out beacuse for the most part it had been running fine after I started it most times (except with the #85 main jet a very few times when going uphill at WOT under high load then abruptly changing to downhill and while turning and hitting bumps at high speed downhill WOT 40-45mph and possibly having a very temporary fuel delivery issue) until I put the bigger main jet in.so I will definitley be looking into that maybe when I adjust the valves I will just throw on the new cylinder tomorrow or whenever I get the bigger jets. I have larger idle jets coming between tomorrow and Friday to test out both with stock bore and bigger iidle jets for the BBK if needed.
Making a more long term fix to my battery wiring that comes loose. If I had the money and time I would order a new wire loom and some switches and be surely done with it. But for now I will sure up the connections and double check that nothing is coming entirely or partially loose during cranking by doing a fairly thorough crank test where I wil shake the bike a bit to see if anything comes loose while sparking and also I don't think my bike has any start failsafes like needing to hold brakes or anything but I think if I do a spark test without holding the brakes and without having a kickstand sensor or anything activated and it sparks---then I DON"T need to hold the breaks and don't have a kickstart stand killswitch built in.??
If I'm missing anything or being dumb in general--feel free to chime in--happy scooting!!
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ratdog
Scoot Enthusiast
Posts: 342
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Post by ratdog on Oct 11, 2018 10:31:39 GMT -5
Frankly, your hard starting issues could be do to low compression. I wonder why you don’t get a can of starter fluid and spray the air filter before starting. Just a thought. Seems like a better way to go then cranking the bike for 20 min. If your problem is from low compression, the starter fluid will fire at a much lower compression then gas will. Low compression is often seen with burning oil. If you are getting blue smoke from your machine, there is an excellent chance that you need rings and, of course, the BBK will solve that issue. Just make sure when you install the big bore kit that you buy and use assembly lube
Starting issues have really nothing to do with the main jet. They have a lot to do with your polit jet and idle setting. And, on the gy6 engines, a great deal to do with it enriching device.
It’s sounds like you might have a “frankenbike”. A stock CDI is not a lot of money, and there is a chance it could cure your starting issues
I mentioned blue smoke from your engine. If when you first start the engine, you get blue smoke, but it goes away after you ride a little, then that is normally an indicator of a valve issue. Normal bad value guides. If you get a little blue smoke all the time and you notice it most when you back off the throttle, then you almost certainly need rings. A lot of BBKs come with a head, so doing a BBK with head would cure both of these problems
I have worked on a few bikes lately with a lot of miles on them. Two have also had a problem I didn’t expect... badly warn cams. They were both 2014 model scoots from the same maker. My pure guess is that they were idleing too slow and didn’t get enough oill on the cam. Of course the same maker, same year also m Ames me think they may have let a few bikes get out that had “soft cams”
One of these bikes had 11,000 miles on it, the other almost 9,000. They cam to me because they wanted BBKs installed. I happen to have a few extra cams around and they had already bought BBKs so they were amassed how good their bikes ran when they picked them up.
Soooo, with very high mialage, I think you would do well with a BBK that includes a head. I would also get a stock cdi
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Post by Sir Scoots-A-Lot on Oct 12, 2018 15:33:12 GMT -5
I haven't noticed smoke when starting. Im not sure why there was oil on the threads of my old spark plug but I am curious as to what exactly it was and why it was there. It looked like it was dirty mixed with gas now that I looked at it again Im not too sure it was even really oily, I think there was some oil and gunk probably mixed with gas. Whatever it was looked wet and was greyish black. I will try to check it again soon. Im sorry, when I saw it and posted about it before I had been outside at about 10pm using a floodlight but still had a time seeing what I was doing very well.
The idea of getting starting fluid and keeping it in the trunk until any starting issues are solved sounds like a great idea Ratdog
I got a new battery (old one sounded low after trying to start many times) and new spark plug, made sure my electrical connections were all good. The new plug fits more snug onto the plug wire boot but somehow the head's female threads where the spark plug threads into stripped a little, never noticed/had that problem with old plug and Im 99.% sure I didnt overtighten the new one, so I got it as tight as I could. Made sure valves were adjusted to a tight .003" so I could barely fit that gauge between after adjusting them. I left the idle speed screw all the way out so it wasnt touching the throttle at all and I adjusted a/f mix to 4.25 turns out still with #94 main #32 idle (planning on rejetting probably both tomorrow unless i do BBK) and it started after 6 or 7 seconds first try! I heard it catching, slowly with the idle down of course and I revved it up a few times as I adjusted the idle screw to proper and boom it sounded like it used to.
I think I probably fouled the old plug with the #94 main. maybe the valve clearance setting worked itself too loose over time as I could fit at least a .005" in both intake and exhaust when I checked before resetting them. I ran the scoot around the block and it never bogged Im guessing because of the new plug but I think I could feel it is too much gas with the 94 main. If I take out the new plug tomorrow I will try to remember to snap a photo and post it although I dont think I followed plug chop protocol too well
I aslo think the weird sound like metal on metal I heard after adjusting the valves a day or two ago was somethiong to do with the starter, NOT SURE but I think that's it. The starter sounds different when I go to crank it and when I was riding for about a week before it wouldnt start I thought i heard something metal rattling under the CVT, Im thinking maybe part of the Bendix was hitting the metal gear on the variator. I looked at the bendix with the bike off and with the Bendix pushed all the way in the starter like its supposed to be it felt a bit loose side to side, not sure if it was always like that or if it now fits into the starter more loosely. On the CVT cover where the Bendix end sits in the cover looks out of shape somewhat instead of smooth and round. I turned off the scoot for just maaybe a half minute and it started up first try and this time the starter sounded about like it used to sound before all these recent shennanigans.
I really wish I had bought the BBk with the head and Cam now Ratdog....I only got the cylinder piston gaskets studs wrist pin clips....I at least need a new head because of the spark plug hole female threads stripping a bit, even if it ran like that so far.
I would be excited to put on the new BBK cylinder but now I am wondering if I am going to have a starter issues. Since I only have the cylinder and piston basic kit do you think I should try putting just that on and see how it goes Ratdog? or maybe just rejet for stock and keep riding it like it is? My goal is just to have reliable transport for the next 2-3 months before I move, I would like the bigger displacement but at this point just want it to run without spending much more becuase Im moving and not sure if Im bringing it with me yet
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ratdog
Scoot Enthusiast
Posts: 342
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Post by ratdog on Oct 12, 2018 18:30:10 GMT -5
My personal feeling is that you have a tried engine. The BBK is like doing a ring job on a tired engine. As far as jetting, if you are thinking you would go leaner, I’d say no. Bb heads are not a lot of money and that would eliminate any possible valve problems. If you don’t get a bb head, I’d suggest you get an extra cylinder base gasket and use two base gaskets to lower the compression a bit from what you will normally get from a BBK ( which frankly is too high to get the bike to run a long time). I wouldn’t worry about the cam. I have only had two bikes with wiped out cams, and they were from the same model and year bikes owned by the same family. When you pull the engine down, you will be looking at the cam and ig there is excessive wear, I think you will reconsider it
If you have a wanky starter, I’m sure you will destroy it with the BBK. I guess I would just order a new one on general purposes. Starters are not really made to crank more then a few seconds at a time. With air the starting issues you are having, I would include getting a new stoc ecu. I really think you have an after market ecu that has the timing fully advanced all the time, and that makes the bike hard to start.
I know, your just seeing dollar signs. The worse part is that there are most likely hundreds of people around you that have all the stock stuff that they took off bikes they molded and don’t bother listing it for sale because it not worth enough to brouther listing
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Post by Sir Scoots-A-Lot on Oct 12, 2018 18:39:31 GMT -5
I was already having issues starting and probably caused more problems by installing that 94 main jet. I thought I was doing the BBK install at the same time but I didnt and still had to use my scooter for transportation. I apologize for that but I appreciate people still taking the time to read this and a special thanks again for Ratdog to being just about the only one answering any of my questions, and with good answers at that
At the same time I did the 94 main jet install I also moved the jet needle clip one notch rich and it seemed my scooter actually started a little better sometimes and idled ok but then ran like garbage and Im guessing it eventually didnt want to start at all because I may have been flooding the engine trying to rev a little while attempting to start it many times with no luck as well as I may have fouled the old and very well used spark plug.
I wish I had more time to work on my scoot, a garage to work on it at nite and in bad weather and more money/better tools. I know I am a green mechanic and even greener specific to scooters but I know if I had additional resources and time I could do a lot better and wouldn't be asking so many questions to try to save time and effort I maybe should be investing to fix it properly.
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Post by Sir Scoots-A-Lot on Oct 12, 2018 18:44:16 GMT -5
My personal feeling is that you have a tried engine. The BBK is like doing a ring job on a tired engine. As far as jetting, if you are thinking you would go leaner, I’d say no. Bb heads are not a lot of money and that would eliminate any possible valve problems. If you don’t get a bb head, I’d suggest you get an extra cylinder base gasket and use two base gaskets to lower the compression a bit from what you will normally get from a BBK ( which frankly is too high to get the bike to run a long time). I wouldn’t worry about the cam. I have only had two bikes with wiped out cams, and they were from the same model and year bikes owned by the same family. When you pull the engine down, you will be looking at the cam and ig there is excessive wear, I think you will reconsider it If you have a wanky starter, I’m sure you will destroy it with the BBK. I guess I would just order a new one on general purposes. Starters are not really made to crank more then a few seconds at a time. With air the starting issues you are having, I would include getting a new stoc ecu. I really think you have an after market ecu that has the timing fully advanced all the time, and that makes the bike hard to start. I know, your just seeing dollar signs. The worse part is that there are most likely hundreds of people around you that have all the stock stuff that they took off bikes they molded and don’t bother listing it for sale because it not worth enough to brouther listing Thanks Ratdog. I already picked out a matching head earlier and I will add up the price of that plus a starter and see if I can make that happen. I hope the new starters aren't too much I was only saying I would go leaner on the main jet if I leave the stock cylinder on and in that case I would still be increasing the idle jet to at least a #35 maybe #38
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Post by Sir Scoots-A-Lot on Oct 13, 2018 21:39:20 GMT -5
I was going to look at my scoot today...but it was cold and raining when I woke up, stayed cold all day and rained at least half of daylight. So....Im now planning on checking out my scoot tomorrow...I guess my plan is to drain all the gas and carb and rejet the carb for stock 50cc and see if it starts and runs ok without any bogging or power loss. If it does run like that Maybe my cylinder and/or head is still good then if I have time and feel up to it I will run to the store to get a couple quarts of oil for my BBK install and I would be prudent to just go ahead and order whatever starter parts I think i need after looking a the starter I guess by taking off the Bendix and starter motor and cranking the starter to listen to it and look at the starter motor output shaft. However they look, if either don't appear close to 100% possibly I will get both the bendix gear and a starter motor because I think they are only $15 on Amazon plus Shipping for the set. Plus I can always keep the starter in my trunk until I need it, looks like a quick 10 min install I could do roadside if need be. Then maybe I can return it after 30 days no questions thru Amazon if I dont need it although Im not sure if shipping would be too much on the return. Last time I complained about a $20 carburetor on Amazon, I told them the carb was awesome but didnt include the extra jet and I asked them if i should return it they just refunded me half--$10---and I ordered 3 jets with that money.
I might also order the new head at the same time but not yet decided 100%, I already have an extra head and base gasket i can use to lower compression. I would rather use my current head to save money if I could be sure the stock head won't give me issues on a 47mm BBK. I suppose I will decide after looking at everything tomorrow. There is a chance if I rejet the main to the 85 and idle to 35-38 and it runs ok that I will just keep the stock setup on there and see if I can get another 1 or 2,000 miles out of it becasue that might be all I ever ask from this bike. I think it would be cool if I take it with me and continue to restore it, eventually take off the plastics and put an led bar on front, replace the half rusted engine hanger...but part of me feels like I should just use it for the time I need it, then give it to a friend in need if it still runs or part it out to others and some for my next build and start over with something in better overall shape. My 139qmb engine doesn't even match the 2 stroke 1e40qmb frame and either when the bike is on the center stand or off (I forget which I think on the stand) the engine hanger rests on the exhaust--I THINK that's as a result of the engine not matching the frame which isnt good and Im surprised the exhaust hasnt come loose yet from that although it appears ok.
Ratdog, if you take the time to read this--what did you mean by a BBK on my engine is like doing a ring job on a tired engine? Do you think it could help solve some issues or maybe isn't worth it since my bike has relatively high miles and a few years on it? I will also be installing 6.5g sliders I got a deal on and when I do that i will check the variator shaft for play to see if the crank bearing appears good from that angle. the clutch and gears don't give me issues but I'm sure they are a bit worn at least
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