I've heard talk in several different places that installing a cam out of an XR 400 dirtbike into a 400 ex will help improve performance. Anyone tried this? Does it work? Something I might consider for my 400 ex.

Mitch
00 Xplorer 400
02 400 EX

 

Works great. Changing to an XR head gasket does too. You can even scrap the base gasket, just use silicone (Honda HT I think) and get just a little more compression.

 

I have one in my (stock piston) 400EX. It was the best $130.00 I've spent on it so far. The cam really wakes up the mid range. It gives up just a little (barely noticeable) on the bottom, but picks up power everywhere else.