rebuild

[exrider249]

I have an 03 400ex. This summer I am going to rebuild the motor. I have already but a hot rod crank in it. But this is my plans for this summer. Wiseco piston 416 10:1 compression, stage 1 hot cam, kibblewhite exhaust and intake valves, kibblewhite spring kit, new guides, new timing chain, new gaskets, and maybe a sparks timing key. Let me know what yall think about this.

Here is a list of things i already have done to it. Wiseco piston 407, hot rod crank, full lrd exhuast, K&n air filter, PRM front bumper, and some other stuff.

[chronicsmoke]

what kind of riding are you planning on doing? If it's anything but tight woods, I'd dump a stage 2 cam in instead with the 416,

You might be able to run a key with that 10:1 set up, but I'll let the experts advise you on that

My .02

[exrider249]

woods, hill climbing, might start xc racing every now and then.

[exrider249]

and will prob do a port and polish

[CJM]

Unless the stock valves are shot (doubtful) then I wouldnt change them.

I much prefer the stage 2 cam on my 416 11;1 setup. The entire RPM band is usable, and unless the woods are very tight Im fine. I can also lug the motor very easily as well.

Timing key will be fine on 10:1 with pump gas IF use a custom +3 key not a +6. Some have been fine with the +6, others have not . I wouldnt chance it.

Good idea to do the chain and guides. Use the 2002 CRF450 timing chain, much stronger and fits great. Also much cheaper than the 400ex one.

All of that should make ya happy.