2005-2009 Honda TRX400EX/TRX400X Service Manual, Page 163Get this manual
CLUTCHGEARSHIFT LINKAGE Install the clutch outer and thrust washer
Install the clutch center and plain washer onto the mainshaftInstall the lock washer with the "OUT SIDEmark facing out
Apply engine oil to the threads and seating surface of new clutch center lock nut and insta ll itHold the clutch center usi ng the special tool and tighten the lock nutTOOL :