What mods are needed to put 450r carb on 400ex

[BigValvedEX]

What all needs to be changed to put a 05 450R carb on a 03 400EX. I see it has wires on it which i think is a throttle position sensor or something of that sort, which i know the 400ex isnt equipped with. Also what are the difference in specs (outer diameter of where it mates up with the intake manifold and intake tube coming from airbox,and also the internal size). How much more air will it flow. I have 1mm oversized kibblewhite intake valves, port and polish, 11:1 piston, and stage 2 cam, K&N, 12 - 1 inch holes in the box lid with the little filters and i am thinking my carb is the choking point of this setup and want a little more top end. Also jetting, i have 170 jets in mine now and it seems to be pretty on, and was wondering about what size of jets i would need in the 450r carb.

[rob-u/21]

There has already been a bunch of threads regarding this. Do a search. I know there is a few threads on this in the Sport ATV Information section.

[jsmith2232]

theres alot of info on this in this forum you can run a search on it but all you need to do is get a 450r throttle cable, hone out the airboot so the larger diameter carb can fit in it (a little heat helps alot also) some guys say you need to move your airbox forward but I just hooked up the carb then stretched the airboot so that my box could reach the mounting holes it's only about a half an inch or so. also you may need to fabricate a different choke lever (I just cut mine so that it doesn't interfere with the petcock and even in 20 degree weather I just pump er a few times and turn the idle up usually 2-3 times and shell be running with no choke) and then jet it accordingly to your setup.