2006-2012 Honda TRX90 TRX90EX/X Service Manual, Page 149Get this manual
CLUTCHGEARSHIFT LINKAGE Apply engine oil to the lock nut threadsHold the prima ry drive and riven gear with gear ho lder, and tighten the anua cl utch lock nut using the speci al tool
TOOL: Gear holder lock nut wrench, 18 mm
On24-0010200 or
On24-001A200 (U.S.Aonly) 07HMA-GN80101 or 07HMA-G N80100