39fcr vs 41fcr [Archive] - ATV Riders Forum

trx440

11-11-2002, 07:37 PM

I've narrowed it down to the Keihins. What are the advantages, disadvantages of the 2 compared to one another. My bike is in the process of becoming a 465 stroker. It will be dune only from here on out.

stupid driver

11-11-2002, 07:52 PM

41 for u if ur gonna be in the dunes

Evan

11-11-2002, 11:19 PM

39 for stock to slightly modded motors.
41 for highly modded to big bore motors.
Either one will work well with anything, its just they are slightly better if u use them for those conditions. I know alot of engine builders use the 39 for their big bore motors too and love it.
I have a 39 and love it. Fits like it was made for the quad.

ChadEXer

11-12-2002, 10:42 AM

A 39 is plenty big for even the biggest bore but after shopping around for a FCR and reading up on them, it says the 39 is for stock to slightly modified(pipe and airfilter) and the 41 is for a bored motor!!

Extremeracer167

11-12-2002, 11:21 AM

I dont know, im running the 39mm on my quad, and its PLENTY! Now im only .120 over, but its still plenty!

powerslider

11-12-2002, 07:42 PM

On a 465 the definitely go with the 41...

Extremeracer167

11-12-2002, 09:24 PM

a 39mm is big enough for a 465. It all depends on the application, if u are looking all top end get a 41, but if u want all around good power, go with the 39!