2004-2009 Honda TRX450R/TRX450ER Service Manual, Page 328Get this manual
CRANKCASETRANSMISSIONCRANKSHAFTBALANCER (After '05) Install the special tool between the balancer drive and driven gears as shown, and tighten the balancer shaft lock nut using the special toolTOOLSGear holder, M1.5 Lock nut wrench, 20 24 mm Extension bar 07724-0010200 or 07724-001A200 (U.S.Aonly) 07716-0020100 07716-0020500 or commercially available equivalent
TORQUE: 54 N-m (5.5 kgf-m, 40 Ibfft) TRX450ER only: Install the starter clutch assembly while aligning its wide cut-out in the splines with the punch mark on the mainshaft
STARTER CLUTCH ASSEMBLY
Install the primary drive gear with the punch mark facing out