FCR Main Jet ? on a 425

[Bansheepops]

I have a Ported 425 with big valves, pipe and no air box. I have a FCR 39 that is not jetted right. Does any one out there have a simular set up and what main jet are you running?:ermm:

[crashinmatt]

well, im not sure how much i can help u, but i had a 416(which has just been bored to 426, but not together yet). not ported and stock head pipe, but in my FCR i am runnin a 168. that shouldnt change much with the different size piston, but i may have to go up one size.

[bmw500hp]

at least 170 according to sparks but thats not wiht bigger intakes