2004 Official factory service manual for Yamaha YFZ450S ATV Quad., Page 89Get this manual
CHANGING THE ENGINE OIL EBS00067
CHANGING THE ENGINE OIL 1Remove: engine skid plate Refer to "SEAT, FENDERS AND FUEL TANK"2Start the engine, warm it up for several minutes, and then turn it off3Place container under the engine oil drain bolt4Remove: engine oil filler cap dipstick 2