2007-2009 Honda TRX300EX TRX300X service manual, Page 164Get this manual
CLUTCH Remove the followinglock nut washer
oi pump drive gear primary drive gear
INSTALLATION
Install the primary and oil pum drive gears onto the crankshaft
Install the lock washer with the "OUT SIDEmark on facing outApply engine oil to new primary drive gear lock nut threads and install it on the crankshaft