i have a '02 400ex w/ a slip on white brothers pipe , i was thinkin of installing a 11.1 high compression piston and a stage 1 hot cam , would i have to install ne thing else such as a clutch ??? and how much do u think this would boost my power , would i be better off goin w/ a 440 kit? thanks

 

you can get awesome power out of the stock bore, 406, 416's, etc. just go with higher compression that stock and a cam. for best power, the stage 2 has suited us well. by the way, we got much much more power out of a full exhaust system. you will feel a difference either way though. go for it.

 

i was thinking of doing the same thing...currently running a WB e-series slip on, k&n, jet, & cdi box.....was going to go with 11:1 wiseco stock bore, cam (WB all-around or hotcams stage 2), and fmf header pipe (hi flo or power bomb).....questions:

1-cam - WB or hotcams?
2-header pipe - power bomb or hi-flo?
3-if you replace the piston with a stock bore size will any machincing of the head be neccesary?
4-how does the set up run????

thanks
tone

 

i don't know anything about the white brothers cams. they may require different guides and/or hardened rockers. the hotcams don't. the hotcams are cheap too. out of those two headers, i would get the powerbomb. i would actually recommend buying a new full exhaust that will outflow that one, but i realize this isn't cheap. you will need to hone the cylinder so the rings seat properly. this setup will run great if you jet it properly and get a cam for your riding style.

 

hey cals400ex....you mentioned you had a 406 piston for sale...what compression, how old is it and how much???....also do you bore your own heads or do you know a place that does for a reasonable price????....thanks