2. INSPECTION/ADJUSTMENT SPORT CUB 125 Eye Hole IGNITION TIMING · The CDI unit is not adjustable. · If the ignition timing is incorrect, check the ignition system. Remove the ignition timing eye hole cap on the left crankcase cover. Check the ignition timing with a timing light. Eye Hole When the engine is running at idle speed, the ignition timing is correct if the index mark on the left crankcase cover aligns with the "F" mark on the flywheel. Timing Light CYLINDER COMPRESSION "T" Mark Warm up the engine before compression test. Stop the engine, then remove the spark plug and insert a compression gauge. Open the throttle valve fully and crank the engine with the starter motor or kick lever. Measure the compression. Compression: 13kg/cm- rpm If the compression is low, check for the following: Compression Gauge 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. 2-6