400ex motor mods???

[exrider249]

I have an 03 400ex with a 416 weisco piston, hot rod crank. I am wanting more power. I was thinking port and polish the head, bigger valves, cam, lightening the flywheel. But I don't know what cam to get. I do all woods riding and hill climbing. I was thinking stage 2 hot cam or an HRC cam. My 450r has an hrc2 cam and I like it. Just wanted to get yalls opinion.

[CJM]

Cam and porting. Then swap to an 04-05 450r carb or fcr carb and of course open airbox. Did you up the compression to 11:1?

[DragonGunner]

Stage 2 cam, port job, high compression piston…lighter flywheel won't be good for woods IMHO, bigger carb with more airflow.

[exrider249]

Its a 11:1 and i will start with the head and then try to find a 450r carb

[Blodg]

The stage 2 Hotcam works very well on moderate 400EX builds like you are describing. If you go to bigger valves the piston may need machined for clearance. I haven't wanted to bother with that so I have stuck with stock valves on my motor. I agree with not lightening the flywheel for woods riding and hill climbing.