1999-2002 TRX400EX Fourtrax Service Manual, Page 89Get this manual
CYLINDER HEADVALVE Removethe upper engine hanger nut, bolt and spacers
Removethe timing hole cap, crankshaft hole cap and valve adjusting hole caps (page3-7),
The crankshaft should be turned only counterclockwiseThis must be done to prevent the onewaydecompressorsystern functioning
Rotate the crankshaft counterclockwise and align the "T" mark on the flywheel with the index notch in the left crankcase coverMake sure that the piston is at TDC (Top Dead Center) on the compression strokeThe rocker arms should be looseIf the rocker arms are tight, rotate the crankshaft counterclockwise one full turn and realign the "T" mark with the index notch