1986-1987 Honda TRX350 FourTrax 4X4, 1987-1989 TRX350D Foreman 4X4 Service Manual, Page 30Get this manual
MAINTENANCE
CARBURETOR IDLE SPEED
NOTE Inspect and adjust the idle speed after all other engine maintenance items have been performed and are withiri specificationsThe engine must be warm for accurate idle speed inspection and adjustment
Warm up the engine for about ten minutesTurn the throttle stop screw as required to obtain the specified idle speedIDLE SPEED: 1,400 100 rpm
CYLINDER COMPRESSION
Warm up the engineStop the engine and remove the spark plugInstall compression gaugeOpen the throttle all the way and crank the engine with the starter motor until the gauge reading stops risingNOTE The maximum reading is usually reached withinseconds COMPRESSION PRESSURE: 125-145 kPa (12.5-14.5 kgcm2, 178-206 psi) Low compression can be caused by:blown cylinder head gasketimproper valve adjustmentvalve leakageworn piston ring or cylinder High compression can be caused by- carbon deposits in combustion chamber or on piston head