2008 400ex engine performance

[racingjosh450]

I have a stock 400ex and I would like it to perform stronger. Can anyone advice me as to what I should do to the engine. My son races Hare scrambles so engine temp is a continous concern with the mud etc.. My intent is to rebuild the engine over the winter months. Any advice you can give would be helpful...Thanks

[tomgodd]

Exhaust, Intake, Cam, Piston, Head work, CDI box.
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