I have a 2001 400ex that i bought about a month ago. everything was fine until it started to get really cold up here in the northeast. one day it just would not start and kept fouling plugs. I brought it to my local dealer and they took the carb off, cleaned it and reassembled it. they told me that the carb was "assembled completely wrong" also. so i got it back in a few days and now it wont start up again. Am i running too rich? do i hav to get a new piston and rings now?

 

Maybe the crank is bad. Look at the top of your pistons and see if there are dents in it....

 

hey if its your crank that is bad i jstu bought a wiseco performance crank for $300 and i decided im not gonna use it with my big bore kit so ill sell it to ya for $250 if ur interested pm me