i put my 11:1 wiseco piston(87mm) and xr cam in my 400ex this friday, the difference is really impressive, im ahead of my friend raptor(he has a filter, jet kit and fmf) and i think is a little hungry! some people said that my motor wont last more thant two month because the crankshaft will not accept the extra power, is it possible?? how many times have your 416 or 426 motor, did you have some problems??
thanks