HOME 3.6 TROUBLESHOOTING COMPRESSION TEST NOTE TOOL NAME PART NUMBER After installing spark plugs, be sure that throttle plate is in the closed position before starting the engine. CYLINDER COMPRESSION GAUGE HD-33223-1 DIAGNOSING VALVE TRAIN NOISE Satisfactory engine performance depends upon a mechanically sound engine. In many cases, unsatisfactory performance is caused by combustion chamber leakage. A compression test can help determine the source of cylinder leakage. Use CYL- INDER COMPRESSION GAUGE (Part No. HD-33223-1) that has a screw-in type adapter.
TOOL NAME PART NUMBER SECONDARY CAM CHAIN MEASURE- MENT TOOL HD-45334 To diagnose and correct noisy valve train components, use the following procedures: A proper compression test should be performed with the engine at normal operating temperature when possible. 1. Visually inspect camshaft lobes for abnormal wear. See 3.8 CAMSHAFTS, DRIVE CHAINS AND CAMSHAFT TIMING, Inspection . 1. See 1.5 AIR CLEANER AND EXHAUST SYSTEM , 1.9 BATTERY MAINTENANCE , and 1.22 SPARK PLUGS AND COIL . 2. If there is noise and engine has low oil pressure, drop oil pan and inspect for metal debris. 2. Connect compression tester to front cylinder per manufac- turer's instructions. 3.
On high mileage engines with good oil pressure, if there is a noise at start-up which goes away, use SECONDARY CAM CHAIN MEASUREMENT TOOL (Part No. HD-45334) to check cam chain wear. See 1.26 SECONDARY CAM CHAIN . 3. Install battery. 4. Make sure transmission is in neutral. With throttle plates in wide open position, crank engine continuously through 5 to 7 full compression strokes. 4. Verify valve lash. See 1.25 VALVE LASH . 5. Note gauge readings at the end of the first and last com- pression strokes. Record test results. 6. Repeat steps 2 through 5 on rear cylinder. 7. variance between front and rear cylinders. 8.
If compression of a cylinder does not fall within its upper and lower limits, refer to Table 3-20 . The cylinder leakage test will pinpoint engine problems including leaking valves, worn, damaged or stuck piston rings and blown head gaskets. The cylinder leakage tester applies compressed air to the cylinder at a controlled pressure and 7.4 MAXI- . When the intake valve has sults. r cylinder. ession reading sh o more than a ten cylinders. CYLINDER LEAKAGE TEST PART NUMBER TOOL NAME ould be HD-35667A CYLINDER LEAKDOWN TESTER percent HD-45314 CRANKSHAFT ROTATING WRENCH TOOL NAME CY C LINDER LEAKDOWN TESTER RANKSHAFT ROTATING WRENCH Table 3-20.
Compression Test Results TEST RESULTS DIAGNOSIS Compression low on first Ring trouble stroke, builds up on the fol- lowing strokes, but does not reach normal. Improves consid- erably when oil is added to cylinder. Compression low on first Valve trouble stroke, does not build up much on following strokes. Does not improve considerably with the addition of oil. Verify valve lash. Same results as valve trouble. Head gasket leak TEST RESULTS Compression low on first stroke, builds up on the fol- lowing strokes, but does not reach normal. Improves consid- erably when oil is added to cylinder. Compression low on first stroke, does not build up much on following strokes.
Does not improve considerably with the addition of oil. Verify valve lash. Same results as valve trouble. 9. To verify worn piston oz) engine oil into ea sion tests on both cy ably higher during th rings. 3-14 2009 VRSC Servic engine toward rear cylinder, as en rings, inject approximately 15 ml (1/2 (00409c) ch cylinder and repeat the compres- 5. Hold throttle wide open to obser linders. Readings that are consider- valve through the intake port. e second test indicate worn piston 6. Turn engine over in direction o SHAFT ROTATING WRENCH ( the valve fully, then close. W e: Engine