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Post by ThaiGyro on Feb 1, 2017 8:24:54 GMT -5
I agree with Vert, something else is wrong...piston hole, gummed up exhaust, who knows? I would tear it down and find the problem...It is just gasket replacement and you can gain valuable information.
BTW...put the airbox back on before you try anything with such a teeny main jet. The airbox question has many posts here, but suffice to say your setup surely cannot work with an "open" filter. Some 4 strokes can...work... and make noise, but not flow properly.
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Post by ThaiGyro on Feb 1, 2017 8:13:18 GMT -5
How is it messed up? Wire cut? Most temperature "sensors" are simple thermisters, in which resistance drops as the sensor element heats up. Simple, unless you have no thermister element. If simply cut, just solder it back on.
If you know the resistance range, or even if not...go to a local electric geek shop and ask. Buy one for pennies. Solder it in...done!
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Post by ThaiGyro on Feb 1, 2017 7:35:10 GMT -5
Haha...all of the above recommendations can work. My addition is to play with one thing at a time, so you can record the results. If you change the port design, then test it! If you find a pipe, test it. You will find better, but not quick results.
Always start with fresh ignition components- Tune your carb- Install a new pipe- Tune your carb- Change port timing- Tune your carb-
That's the general idea! Every little thing you do has some effect on the other components operation.
I am building a new pipe too. Going to run it with OEM carb, (tuned) and ignition (pre-mix fuel)...then the unrestricted ignition change, then change the timing advance, then the carb, then tune the carb until it is what I want in a 50cc.
I currently only have a butt-cheek dyno, so it is important to be methodical.
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Post by ThaiGyro on Nov 1, 2016 6:11:09 GMT -5
Sooo much good advice here. When I raced two strokes 125',250's and OMG; I did many, many plug "chops". Since those days, I have learned that street bikes should be attended to at their operating range. Do you run down the street wide open? Yes, but every moment?
In my opinion, you should "tune" for you intended range of flow. Maybe a bit tough, if you like sudden throttle response, but not all that hard. You can actually get a plug read at ANY rpm...and know what your systems are doing together. Top end reading is easy, but best for racing, I think.
Some like EGT indicators, while others tune for O2 reading. On a 2 stroke, either one is a challenge, due to unburned oil residues, but both indicators of combustion. The trick is to get your tuning without fancy and expensive gadgets. Experience, properly applied.
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Post by ThaiGyro on Nov 1, 2016 4:17:42 GMT -5
I must ad my pennies worth here. Vert and quite a few others, really know their stuff when it comes to high performance tuning. I get a bit tired of long threads from short experience people...all well meaning, but any one of you has a different setup, engine, electronics, age, and many more factors.
The real deal with tuning...OK, this is a thread on chambers: Think about what things you can change to make "performance" happen. Carb size and jetting? Ignition timing? Port timing? Exhaust chamber design?
The answer is you bet to all! I have tuned a Yamaha Rd 350 to kick the poop out of "high quality chambers". The reason is that the stock exhaust was really good. Modified it would make more noise and maybe more bottom end, where most folks like to be.
If you want more performance for your money? Start with proper tuning of your stock engine! No leaks, no sputtering, clean and crisp throttle response. All of that will get you both big smiles and great fuel economy.
If you desire more? Do one thing at a time and tune to that one thing! New ignition timing? Tune for best response on the fuel end. New carb? Tune the carb first, then look at ignition improvements, then make little adjustment again.
Change the exhaust? Do all of the above, starting as described. Carb tuning, ignition tuning, carb tuning again...Ohhh, and all of that under the same atmospheric conditions. When you get to be 60 years old? You may laugh and have fun!
Racers modify ONE THING...then test. Modify for the test results...then test again...and again...and again. Heck, laps around the block are easy and cheap compared to track time.
Last, regarding expansion chambers. You MUST know what it is designed to do! Pull your eyes back in your sockets off the line? Hit hard at 7000 rpm to redline? Only top end power, like a drag bike? Or...balanced power over the intended RPM range? It is all fun, but all different tuning...tuning to the pipe and engine design! Pipes are easy to mount, but expensive to buy, as are engine mods. Carb bits and ignition tuning may seem a pain, but are cheap labor.
That should be less confusing than trying to play with 10 different opinions.
..and then there is roller weight tuning...
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Post by ThaiGyro on Aug 13, 2016 4:46:50 GMT -5
It is also possible that someone converted your original stator to full wave...many scoots are only half wave. Cost saving at the factory, I guess, but if that is true, they would also have to use a full wave rectifier.
If your scoot is fuel injected, it would likely have a full wave system to begin with....I know my 2014 Yamaha Mio 125 is full wave, but my '85 Honda Gyro is half and old and doesn't charge a watch battery.
If you check your rectifier part number, you can get an idea.
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Post by ThaiGyro on Jun 10, 2016 17:43:49 GMT -5
The pipe is that close? Seems counter productive to have a single sided mounting that requires exhaust removal. Loss of sex appeal for me. Lack of functional engineering is bad engineering. But...I have a Honda Gyro. Many curious parts and functions.
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Post by ThaiGyro on Jun 10, 2016 17:27:04 GMT -5
Just found a Honda race bike picture on my FB pages... This was the most fun I have had on the racetrack...
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Post by ThaiGyro on Jun 2, 2016 2:17:03 GMT -5
I say try it as well. StepThru is correct..if properly designed they can give better throttle response in midrange. You might do well to study the port shape and taper. All the stuffers really do is create more flow at the reed port. We used to build Yamaha RD350's with them. My personal opinion is they should only reshape the intake charge while slightly boosting velocity. Sno-mobile guys have done some dyno testing and remove them when they want more top end. Be very careful of the material you choose. I have seen some plastics that crack over time with too much heat... This was on a Yamaha GP1200 personal water craft. NOT a stock Yamaha part. The design is not good at all. We used to buy Melamine blocks in 1 inch thicknesses or 1.5, then cut it to fit the port..and grind the opening. I could not find a picture of one we did...too old. There are many on the web and various forums. It is my understanding that Malossi makes one for an Aprilia VL 12 that you can buy with their reed block, but I have not seen it.
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Post by ThaiGyro on Jun 2, 2016 1:39:27 GMT -5
I am curious how they broke an exhaust "stud" while changing tires. I would run far, far away from that shop.
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Post by ThaiGyro on May 3, 2016 20:10:37 GMT -5
JDL...not sure about todays preferences. I came from the oil & gas business. In my racing days, we broke in new rings with Castrol original oil...which was and still is castor oil with some quick burn additives. After seating the rings, most people switched to as synthetic. Just FYI...
The ratio is really determined by many factors. Ambient temperature...humidity...the oil...timing curve...port timing and chamber design. All have varying effects on what you really need at any given moment.
Most people find and use a ratio that burns clean, prolongs plug life and performs. To give you a range...air cooled racing 2-strokes in the 70's were 16:1, up to 20:1, but timing advanced toward detonation, even with huge carbs & main jets and colder plugs.
Todays bikes can be run anywhere from 25:1 down to 40:1 ratios, again, depending on the many factors. If you read these pages, I think you can get a good picture, but find an expert in your area is my advice.
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Post by ThaiGyro on Apr 28, 2016 6:38:22 GMT -5
I am sure that all Japanese twin tube, under-bone bikes are following what the racers have done. Here that is increasing displacement, bigger cams, and better gearing. The Thai versions of Honda and Yamaha both went to 150CC with a bit more than 11:1 compression and fuel injected six-speeds. Bump the compression higher even and the 13,500+ rpm's would provide some fun. The Suzuki and Kawasaki are similar, but I don't know the details. I think they are all in the 16.5 to 18 hp range, with DOHC setups. Should be 20+ in the right hands...especially with fuel injection and better ignition mapping.
I do know that they all have upgraded suspensions and brakes as well. Everything is liquid cooled. It's all about A-F and exhaust flow.
I find it interesting that there are still many 2 stroke under-bone bikes here that can either keep up or in many cases smoke the newer 4T's. I saw both a 125cc Kawi and a T135cc Yamaha (4T) having a great time at the race track, with no other four stroke able to keep up. The Kawi was faster than the Yamaha! Very skilled riders helps too! They were many seconds ahead of the Honda and Suzuki 150's. Not a good comparison, as I have no idea how any were modified, but were all racing in the 150cc class.
I am sure I can poke my nose into a few shops or pits and find more details.
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Post by ThaiGyro on Apr 25, 2016 8:55:47 GMT -5
Someone asked for old racing pictures...only found one from '76 or '77 on a Yamaha TA125B. This is from Riverside Raceway. Start of the race, entering turn one. Look for Black/Red/Orange/Yellow. Not a great picture of the bike...
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Post by ThaiGyro on Apr 16, 2016 4:09:00 GMT -5
Your question is a great one. Often much confusion about water systems. Lucas has the good answer. Though I have not done calculations, and probably won't...a simple electric pump that can handle both 230 degrees F, (110 C) and about 15 psi. system pressure. (1.03 bar) Cooling here is all about proper residence time...in the radiator, but really? Fancy calculations is my life and a great waste of time here. Ryan and Lucas have parts of the answer. Our engines will produce some fairly high temperatures. Sorry, I do not have cylinder or good head temps,(230 degrees at the head?) but do have exhaust gas temps. What is important to know about water cooling is that you do NOT need high flow, but do need variable flow. It is more important to understand heat removal. Of course, actual data is priceless, but you can infer much from existing bikes and parts. The radiator you have is probably bigger than required, though that does not mean it will not work. The Malossi 12V pump is near perfect for the job. Designed for the Pressure and temperature profile already...and low battery draw. Mount it to draw liquids from the coolest point of the radiator...at the bottom outlet. Keeps it cooler and consistently working with the highest possible suction pressure. Note that it is a centrifugal pump, which is the right design for the system. The 12V water pumps designed for motorhomes water systems is a sketchy and potentially problematic design. They are "pulse pumps", meaning near positive displacement. Often diaphragm or wobble plate or similar. They last a long time pumping water...probably the right flow regime, but that is it. The drawbacks are simple: Noisy...maybe designed to handle high temperatures, maybe not? They cannot handle being dead-headed, so need an auto shutoff. Mind you, the same design is used in cars and diesels as a lift pump, but again, must have a shutoff switch. My '01 Dodge Cummins ate them up! Not from the temperature in this case, but from the variable pressures...engine needs/fuel liquid head pressure...high pressure pump demand. Cheap though? Buy one at any RV supply. You also must ensure that your flow routing is up flow on the engine side...coolest water in the bottom, from the bottom of the radiator, hottest out the top, through the thermostat to the radiator inlet at the top. What is not commonly known is that radiators, besides being many sizes, thicknesses and number of core rows, work best if the flow is cross flow. meaning side to side. Top of hot inlet, up and down and up and down....until the flow reaches the bottom outlet. Some dirt bike radiators or simply top to bottom, or have two...the bottom of the first feeds the top of the second. Cross flow works. Most importantly, consider the use of your scooter. A drag race scooter is one and done! Shit and git! They very likely do not have a thermostat. Just enough cooling to be on the edge of holing a piston. You will need a thermostat! It is the thing that will allow your other components to work properly. There are in-line thermostats, get one. Mount is near the cylinder head outlet. If you chose to monitor temperature on the water side, do it after the head, but before the thermostat. My belief is that you should know what the engine is doing, not how well the thermostat is performing. Further, it tells you if your overall cooling is adequate. ( I monitor exhaust gas temps, cooling water and cylinder head. Maybe just so I know what to tear down first when I blow it up.) The low pressure pumps are simple and easy, but centrifugal pumps can withstand no flow, (Thermostat closed) for short periods. That is why all cars and bikes use centrifugal pumps. What causes the wear at the pump face is a few things, but the two common causes are dirty system liquids and cavitation, (intermittent flow)...not no flow. In other words, you can have a real big radiator and still have it do its job. Too big and the thermostat stays closed longer, potentially causing large temperature swings, which can cause both performance changes and premature failures from metal fatigue. So you need a design with: * Down or cross flow Radiator *Thermostat *12V pump *Proper hose routing *Fan *Overflow bottle (If you overpressure one time...you'll know why!) The use of a fan is actually somewhat optional, however it is cheap and easy protection. If your radiator is oversized, the fan may never come on...(I know people who prefer this to eliminate a fan, but select a thermostat temp. and hope for the best)...undersized and it never shuts off. I have a fan that is switch mounted...only used for extreme duty on my air cooled engine. If you put one on a water cooler, make it temperature controlled. This one from Trail Tech, has a built in display! Cheap, good looking and functional. I use expensive silicon hoses, but just because they look good...no debate over function needed. I do not believe that they "perform better" than rubber in thermal terms. IT is a good argument, if you're pumping bazillion rpm's/hp, what ever. Not sure if measurable in our systems, even if 95cc conversions. But again...they look cool!
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Post by ThaiGyro on Apr 15, 2016 18:23:42 GMT -5
I have worked with their Customer Service many times. They are great. They recently changed their website, had some issues that immediately fixed by a guy named Zack, Just write your request to this sales@trailtech.net, and they will quickly respond to tell you what info they need. Looks like Ryan covered the length issue. Should be fun and easy. I have done their stuff on Yamaha XS650 twin, Honda Hawk GT650 V-twin, a Yamaha WR250 and YZF400, I have one waiting to install on my Yamaha TRX850 here in Thailand. I too will put an aftermarket dash on my Gyro. I am also looking at Koso. Seem to be popular here kosonorthamerica.com/I have found that the speed sensor on some bikes is the hardest to mount, but only due to the caliper shape. If you have a drum it would b a different mount, but a bit easier. Good luck! Post pictures!
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