400 w/ 450R engine??

[atvRiDa400ex]

hey, i have been wanting more power outta my 400ex and i dont want to go but a new 450R. so i was wondering how hard it would be to swap the motors or if it is even possibe. And should i be putting a TRX450R motor in or a dirtbike 450 motor in? i dont want to do any mods to the 400ex motor like bore or anything like that. also will 450R plastics fit a 400ex with a lil help or no? All proffessional opinion would be great. thanks
:ermm:

[300EXrider356]

The motorwould work with a little welding for new mounts and radiator mounts. I have herd that that the rear shock has to be flipped around so it will fit, which then its the airboot, so a new one needs to be made. I woud put a crf motor in unless you havee an 06 450R engine because the CRF is a little faster. But remember that the Dirtbike engine is a backword kick so youll have to trim your plastics and what not. Hope I helped.

[strapped9]

they sell 400ex-450's plastic conversion kits on ebay. serach it up.

[krt400ex]

the motor will work with a few modifications to the frame mounts and such. i would get the '05 motor. theu r so smooth and they make gobs of torque

[400exMO]

1fst400 (i believe that's his name) just did the 450r motor in 400 frame conversion. The only time I'd suggest that is if you have enough money everywhere else in the bike that it'd be a big lose to upgrade to the 450. But if you're set on it I'd get a crf450 engine and send your frame to JB Racing to build the custom mounts.

[krt400ex]

actually i was planning on putting an '05 450r in my 400ex after i get my truck in 1 1/2 yr.