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. 3-7