1998-2001 Honda Fourtrax Foreman TRX450S, TRX450ES Factory Service Manual, Page 128Get this manual
CYL NDER HEA' CYLINDERPISTON D
CYLINDEROMPRESSION TEST C
If the engine must be running to do some work, make SI1r8 the area ;s well ventilatedNever run the engIne In an enclosed areaThe exhaust contains poisonous carbon monoxide gas thar may cause Joss of c,onsc.iousns'S$ and may lead to de'a thRun tIren'g ne In an open area or with an exhaust e
evacuation system ;n enclosed area
Warm up the engil"leStop the enginaand remove the spark plugInstall compressIon gaug eOpen th th rOltle all the way and crank the eng ne ith the Slsrter motor until the gauge reading stops rising
Compressi(",'1 pressure:
539834 kPa 15.58.5 Icgfcm 2, 78121 psi) at 450 Ir pm
II compression is be low than the standard, 100sel1 the exhaust valve I:ock nut and turn he adjusting, screw 1-121umand recheck the compressionCompression pressure: 1.226',442 kPa (12.514.5 118206 psI) at 450 rpm Low compression can be caused by:Blown cylinder head gasketImproper valve adjustment