Yamaha YFM660RN Service Manual

Contents

3 - 19CHKADJMEASURING THE COMPRESSION PRESSURE/CHECKING THE ENGINE OIL LEVEL***********************************************Measurement steps: Crank over the engine with the electricstarter (be sure the battery is fully charged)with the throttle fully-open until the compres-sion reading on the gauge stabilizes.WARNINGWhen cranking the engine, ground thespark plug lead to prevent sparking.***********************************************7.Install: Spark plugCompression pressure (at sea level):Standard:1,250 kPa (12.5 kg/cm 2 , 181 psi)Minimum:1,050 kPa (10.5 kg/cm 2 , 149 psi)Maximum:1,350 kPa (13.5 kg/cm 2 , 192 psi)T R..18 Nm (1.8 m • kg, 13 ft • lb)CHECKING THE ENGINE OIL LEVEL1.Place the machine on a level surface.2.Start the engine, warm it up until the engineoil has reached a normal temperature of60 °C (140 °F), let it continue to idle for tenseconds, and then turn the engine off.NOTE:To achieve the proper engine oil temperaturefor an accurate oil level reading, the enginemust have first completely cooled down, andthen warmed up again for several minutes tonormal operating temperature.