i recently got a new tct a couple weeks ago and it was a pretty big deal. a $40 part is no small investment for me and i was going to get my money out of it. my brother and i both have coleman bt200x mini bikes with stock engines and have been doing small mods to add power. i modded mine about as much as i could with the stock parts and it got to the point mine was quite a bit faster especially at higher speeds. it had two noticeable power bands, by my estamation right off idle and again around 3500 rpm. so it got to the piont i could easily leave my brother behind when i wanted on road. but we were equal off road. going through open trails i was still faster but through "un-edited" woods they performed the same. anyways he wanted more power so we got it and it was... disappointing. from what ive seen online a lot of people are having problems and i think ive solved about all of them so lets get started. first and foremost it was not any faster. it seemed to remove any power band the engine had and it revved a little faster when we got any air time. not one to easily give up i kept working on tuning and doing research and learning how the thing was put together and its actually super simple. we eventually got it working about as good as stock and it didnt have any power up high so we bi-passed the governor with a ziptie and used it like that. but yesterday we took it riding with a freind and when holding it pinned for about half a mile it started to rev out and actually run decent at higher rpms! that was kinda a hint for me so as soon as i got home we pulled it off and started investigating. also dont be afraid to take this thing apart its super simple! just the visible screws on top and the little throttle lever that needs pulled off. underneath youll find a cam like sloped lever and the needle with a little roller as well as a spring that pushed the needle-roller against the cam. the first problem i found was the spring was just not strong enough to hold the needle pressed against the cam so it was acting weird. also DO NOT OIL THE NEEDLE. the clearances are very small and oil makes it very stiff to move. ask me how i know. so to fix the spring i just very gently pulled and stretched it about 1/4 inch, kind like you used to do with pen springs when you were bored in school. that made it stiffer and hold the needle. next, with it all resembled i noticed that the little throttle lever on the top is not going fully to 90 degrees. so there are three parts, ill name then real quick lol. the part the governor linkage connects to is part 1 the linkage is part 2 and the part that actually moves the butterfly valve and the cam is part 3. so part 2 snaps between 1-3 and keeps them in sinc. the snaps though are poorly made and wear out really fast as well as have a lot of slack in them from the factory. meaning part 3 doesn't move as far as part 1, luckily there is an easy fix. there is a little lump on part 1 that stops it from moving to far and pulling the other parts past 90, just take a file and sand paper to the very soft plastic until the parts move as far as needed. 
i think thats about it for the carb. just tune it and for some extra performace just take your dremal and chamfer all the edges in your air box and muffler for better flow, gap the plug a little wider and polish your valves and feel the power! it really does just keep pulling very consistently and at very low revs. we are both a huge fan of how the power comes on and it just pulls. we use ours for pulling our little trailer and all kinds of things so im happy to have the extra torque. Ask any questions ill be happy to answer!
i think thats about it for the carb. just tune it and for some extra performace just take your dremal and chamfer all the edges in your air box and muffler for better flow, gap the plug a little wider and polish your valves and feel the power! it really does just keep pulling very consistently and at very low revs. we are both a huge fan of how the power comes on and it just pulls. we use ours for pulling our little trailer and all kinds of things so im happy to have the extra torque. Ask any questions ill be happy to answer!
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