2006-2014 Honda FourTrax ATV TRX250 EX TRX250X Service Manual, Page 122Get this manual
CYLINDER HEADVALVECAMSHAFT
CYLINDER COMPRESSION
Warm up the temperatureengine to normal operating Stop the engine and remove the spark plug (page 4-9)Install compression gauge into 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 kgfcm2, 185 psi) at 800 rpm (min-')