2004-2005 Honda TRX450R Factory Sevice Manual, Page 52Get this manual
MAINTENANC E
VA LV CLEARA NCEDEC OMPR ESSOR SYSTEM
InSDetl and .aj us vlve ""d decompressor clearance hile Inc eng Ine icold (be low 3519 5"F)
VALVE CLEARANCE INSPECTION
Remove the cy linder he.d cover (page 961 Remove the ran ksha ft ole oa p
Rota te he cr an kshalt' u" ""mark on the rimary rive gear with the ind on the cran kcase cover Make sure th piston;s al TDC Oe"d Oil the compressio stroke