Maybe someones been down this road but i just picked up a 400ex which has alot of work done on the motor. has 440 kit, stage2 hot cam, heads ported, and the rest of the usual goodies. It has the stock carb w/ the choke removed but i was wondering if it was worth swapping another carb into it? It runs good with the stocker but if a larger carb would benefit it, I would just rather finish the job right. I see alot of people swapping in the 450r carb and a few people i talked to said the edelbrock (eichner) was designed for it. Just wanted to see if anybody had an opinion on it or maybe had done some tinkering with theirs. Thanks.

 

You will definetely benefit from a larger carb, and you may want to look into a stage 3 cam if they make it for the 400EX's, I know they make one for the 450R's for big bore and stroke applications. As for which carb to go with, I'm not sure what size your bike originally came with, but I see nothing wrong with the 450R carb. You'll likely find the 450R carb cheaper than an aftermarket carb to begin with, but if you want solid performance, I would go with the eichner or maybe even call up someone like Sparks to see what they offer.

 

The 450R carb is a slide carb that will give better response than the stock 400ex carb. I put one on mine and it did give me more power but, I was never able to tune it in and it was a gigantic pain in the a to make it fit in the stock boots. I hated pulling the thing off and was ready to rip it off and put the stock back on but I sold it first.