2001-2005 Honda TRX250EX Sportrax TRX250EX Factory Service Manual, Page 91Get this manual
CVLINDER HEADVALVE
CYLINDER COMPRESSION
Warm up the engine to normal operating temperatureStop the engine, disconnect the spark plug cap and remove the spark plugInstall the compression gauge with the gauge men! into the spa rk plug hole
Shift the transmission in neutral and open the choke
lever (OFF) Open the throttle all the way and crank the engine with the starter motor until the gauge reading stops rising The maximum reading is usually reached with-
in 4- secondsCOMPRESSION PRESSURE: