3. INSPECTION/ADJUSTMENT MXU 300/250 Compression Gauge 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. Cylinder compression: MXU 250: 15 kg/cm (1500 kPa, 213 psi) MXU 300: 16 kg/cm (1600 kPa, 227 psi) 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. Upper Level ENGINE OIL OIL LEVEL Place the machine on a level place. Warm up the engine for several minutes and stop it. Run the engine for 23 minutes and check the oil level after the engine is stopped for 23 minutes. Inspection Window Lower Level Check the oil level through the inspection window. The oil level should be between the maximum (H) and minimum (L) marks. If the level is low, add oil to raise it to the proper level. 3-10