I have been kicking around the idea of getting a set of 35mm FCR carbs for my Raptor. The reviews have been good indicating I would gain both power & throttle response. However, I have heard there can be fitment problems with certain mfg exhausts. I have a full Yoshi system & was wondering if anyone is aware of a fitment problem with the Yoshi exhaust? Any advice would be appreciated, even if you just want to talk about a different exhaust that it works well with. Thanks.

 

UBETRUN, Airrap, and a few other guys I can't remember off the top of my head have run this setup at one time or another I believe. When I see them post they usually say that with the right placement of some spacers/washers that it will work.

 

It doesn't fit well with the Yoshi, it fits great with a Sparks x-6. It can be made to work with a Yoshi but it might ruin your exhaust if you're not careful. Slip a couple of washers in between the upper frame rail and the side of the upper motor mount on the exhaust side. You might need to pry the upper frame rail to get the washers installed. If you still need a little more room, you can use a big c-clamp and slightly squeeze the mid-pipe at the carb accel pump. You don't need much clearance, 1/4" is plenty. If you squeeze the head pipe too much, you'll have a heck of a time getting the muffler off.

 

So ubetrun, what your saying is to crush and deform your yoshi system right where the head pipe and mid pipe joint together and hope you have the right tools, money, knowhow, patience and CLEARENCE in the end with no leaks where at the pipe joint and hope everything works out there really isn't enough room for this mod combo and won't work with the stock headpipe either, its even if you could believe really just a bad design by keihin they picked the worst possible place to put the accelerator pump, and no heat issues from the exhaust to the accelerator pump, keihin should have just put the accelereator pump on the outside of the left carb, there is all the room in the world over there I don't know what they were thinking with that and they should definately redesign there FCR set up for the raptor, Oh yeah, to who ever is listenining go with 39mm FCRs on the raptor not 35mm FCRs, stock bike or whatever, you can always jet up or down.