1999-2002 TRX400EX Fourtrax Service Manual, Page 136Get this manual
ALTERNATORSTARTER CLUTCH LEFT CRANKCASE COVER INSTALLATION
I nstall the starter reduction gear and shaftCoat new O-ring with oil and install it into the starter motor groove
Install the dowel pins and new gasket
Install the left crankcase cover, being careful not to pinch the neutral switch wireInstall the nut and seven bolts, and tighten them securely