I like all of the things that I've been hearing about the Keihin FCR carbs. I've noticed that a lot of people are putting them on thier 400EX's. But I was wondering how well one would adapt to a kick start motor like a big bore 250X engine? How do they start cold? I am currently running a stock 400EX carb on a built 330EX motor, and it mounts up perfectly. So if a FCR fits a 400EX without mods, it should fit a 250X/300EX also. I would like to hear opinions from the owner's of this carb, before I spend the money to buy one.
Thanks for your time.

 

Nothing......No one.......

Maybe I should as a question about drag racing. Then I could get about 70 responses.

 

LOL Cstark. You should ask "which would be faster,a 400ex or banshee" first. Then after you get people responding ask your serious question. Anyway, im sure that the FCR would work with your motor. You would have to adapt jetting of course, but im sure that it would work ALOT better than your 400ex carb.

 

lol, or you should have asked either what exhuast, or what mods for my 400EX....
i would also consider a bigger intake boot too, people say that one from a 350X motors work great, but i don't know how they compare to the 400EX one. in this case, bigger is better.

 

I don't plan on running an airbox at all. This will be a pure MX machine for closed course racing only. If at all possible, I will mount the filter right on the carb(with whatever mods are nessecary). My main concern is how well does the carb operate? How touchy is jetting? Fit and finish of the product? That type of thing. I'm not looking for other setup tips.
I have a 330EX for XC racing and trail riding. It runs a 400EX carb and works great. But I'm looking for more power. I am racing against "A class" 440EX's and power-valve 265r's with a 350 4-stroke. Chassis(Laeger) and suspension(Custom AXIS) are up to par. But can I get enough out of the motor to have a chance? I think so. A 340lb, 40+HP 4-stroke is a very lethal weapon.

 

I have a FCR on my 440 and it seems to keep working better. I had some trouble getting to fire at the beginning but it seems to have passed. It kind of remined me of learning to kickstart a 4/stroke--Once you get it its simple. Jetting no problem....