2004-2009 Honda TRX450R/TRX450ER Service Manual, Page 327Get this manual

2004-2009 Honda TRX450R/TRX450ER Service Manual, Page 327

CRANKCASETRANSMISSIONCRANKSHAFTBALANCER (After '05) Install the balancer driven gear to the balancer shaftwhile aligning its tab with the clinched tooth of thebalancer shaft
Install the balancer drive gear onto the crankshaft by aligning the wide groove with the flat tooth (punch mark)