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I ordered a complete Lifan wiring harness as a template, so as soon as it gets here I'll be able to start producing the harnesses. I spent all day riding around and went to my brothers for a few hours crunching massive amounts of numbers figuring out engine performance and we came up with figures that were depressing. A stock engine running a stock carb with stock exhaust produces 16HP, we all know this from stats on the web sites well thats confirmed. Now here is the kicker replacing the stock carb with a 30mm will not increase HP at all, in fact it would be just like your running rich on the mixture and risk detonation. Air/fuel volume versus actual engine combustion chamber cc doesnt add up one bit. Stock engine displacement isnt capable of burning the extra amout of fuel without problems, in other words theres not enough room in the chamber and the compression is to low. But hey, what do a couple of jet engine mechanics know....lol. In order to to use a 30mm carb the modifications will be as such: First you would have to increase engine cc to 238cc or better, up the compression by 9:5.0 ration, tune the cam for a smoother exhaust ramp profile and intake open duration, (takes a deep breath) port the intak for an increase air volume passage, and design a pipe which will provide enough back pressure. With these mods your going to have a 250cc engine producing roughly 28HP, for quick math. 200cc = 16BHP, adding 50cc will be adding 4 more BHP for a total of 20BHP for a stock 250cc engine. If all the mods were done you will have a total gain of 12BHP. Now those numbers above arent actual just a reference if you want to really do a conversion you would have to do this. Divide cc by 16.4 to get cubic inches the final figures arent exact because you have to factor in mass volume and compression and that a totally different animal so you see, this isnt an exact science due to alot of factors you have to account for and geography is one of those factors being most engine manufacturers base figures on absolute ambient temperture at sea level. We used the same formulas used for turbine engines and automotive engines and came up with the same results. So if your thinking about adding a 30mm carb to a stock engine, Id say sleep on it.
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