kxr 50 90 Workshop-manual : Page 50

          3. INSPECTION/ADJUSTMENT                                             Mongoose/KXR 90/50


 SPARK PLUG
 Remove the ignition coil cap and spark
 plug.
 Check the spark plug for wear and fouling
 deposits.
 Clean any fouling deposits with a spark
 plug cleaner or a wire brush.
 Specified Spark Plug:
 (Mongoose/KXR 90): NGK: C7HSA
 (Mongoose/KXR 50): NGK: BR8HAS
                                                                  Ignition Coil Cap/Spark Plug


 Measure the spark plug gap.                       Gap, Wear, and Fouling Deposits
 Spark Plug Gap: 0.60.7mm
 When installing, first screw in the spark
    plug by hand and then tighten it with a
    spark plug wrench.




                                                  Washer Deformation        Cracks, Damage



 CYLINDER COMPRESSION
 Warm up the engine before compression
 test.
 Remove the spark plug.
 Insert a compression gauge.
 Open the throttle valve fully and push the
 starter button to test the compression.
 Compression:
 (Mongoose/KXR 90): 16kg/cm
 (Mongoose/KXR 50): 12kg/cm
                                                 Compression Gauge
 If the compression is low, check for the
 following:
 - Leaky valves
 - Valve clearance too small
 - Leaking cylinder head gasket
 - Worn piston rings
 - Worn piston/cylinder
 If the compression is high, it indicates that
 carbon deposits have accumulated on the
 combustion chamber and the piston head.



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