Completly Confused NEED HELP

[goggo]

Ok here is another jetting Question in my old motor i had open air box uni filter 28mm keihin prox hi comp piston lrd ajustable pipe and porting and i ran a 150 main and never had a problem now i am putting in a CT 240 kit ported and all the good shit with a 36mm mikuni and all the same other stuff and in the carb now there is a 330, (stock is 230) these 3 numbers have a huge gap and i need a good baseline to start jetting the machine and i have no idea where to start and why did my other machine not blow up with a 150 by the way i live in minnesota and ride in the summer i have no idea what the elevation is please help

[MaineExport]

Keihin and Mikuni run different numbers for their jetting... that would be my assumption. My Trenga 240 (similar to your CT) with 36mm Keihin, aluminum air box, uni filter, Prodesign intake, V-force reeds, and LRD exhaust runs between a 178 and a 198 depending on elevation and air temps. I'm not sure what size Mikuni jets would be needed with this setup since I've only used the stock mikuni and aftermarket Keihins... but a very rough guess would be a tad over 300... 330 sounds kinda fat. But... you can probably contact CT and I bet they've dealt with your carb once or twice and they could give you a real good starting point.


I'm guessing that your other top end didn't blow up with a 150 because that happened to be about the right size. It sounds small to me... but if you're in high elevation and high temp it's not impossible.

High altitude (= less oxygen density) + high temp (= less oxygen density) = smaller jet required to pull back the amount of fuel in the mixture to match.