2006-2009 Honda TRX250EX/TRX250X Service Manual, Page 127Get this manual
CYLINDER HEADIVALVECAMSHAFT
CYLINDER COMPRESSION
Warm up the temperatureengine to normal operating Stop the engine and remove the spark plug (page 4-9), Inst all compression gauge int the spark plug holeShift the transmission into neutralPush the choke knob down fully (OFF)Open the throttle all the way and crank the engine with the starter motor until the gauge reading stops risingThe maximum reading is usually reached withinsecondsCOMPRESSION PRESSURE: 1,275 kPa (13.0 kgfcm 2, 185 psi) at 800 rpm (min-1 )