450r motor in a 400 ex

[Lvnspeed]

450r motor in a 400 ex

Has anyone done this? Was there any major gains? Any down sides?

What about link to where people have done this?

[400exrider707]

Search for the user name 1fst400 he has one, its pretty sweet, I always wanted one, the 400ex frame hanldes better and jumps better IMO, but the 450 motor will probably tear that frame to shreds... try PMing him or searchign for his username, you will find his build.;)

[miller821]

Search this in the Hybrid section, plenty of threads in their about this.

[Lvnspeed]

After spending most of the day at work searching around I have found answers to almost all of my questions.

from what i can tell, yea its the way to go.

So I see it I need the following to take a stock 400 with 450r shocks to a 400 ex with 450 shocks and 450r motor I will need the following right?


motor 450 r
wiring 450r (do I need this?)
radiator 450r (right)

Oh yea and som fabericated parts right?

thanks for the help.

[Barrymaxx]

Your going to need everything that relates to the 450 motor.

Even the clutch and throttle cables, carb, exhaust/header, rad, hoses(probly have to make your own), the motor itself, kicker(may have to be modded) shifter, complete wiring harness.

Probly more

[gcart2]

call lonestar tell them what u have and what u need. they will help u 100%. also u need exhaust cooler etc for the motor

[250x_kyle]

well if the frame is gusseted and moddified right the frame will not rattle apart. saying this because of the fact that ppl are putting yzf450 and crf450 motors that a cranking outmore power than that in stock non gusseted ex frames. just take the time and do it right and you wont have a problem. and you will need the 450r motor carb and wireing of course. but you do not have to run the r radiator it would be easier but not neccesarly a must. your coult run an aftermarket r radiator just have to get hoses that will fit. the only part of the exhaust you would need is a header you can make your own custom mid pipe and you might have to mod the slipon and the header for the mid pipe.