| PART NUMBER | TOOL NAME |
| HD-33223-1 | CYLINDER COMPRESSION GAUGE |
Combustion chamber leakage may cause performance issues. A compression test can help determine the source of cylinder leakage.
Test engine at normal operating temperature
1. Disconnect spark plug wires.
2. Clean around spark plug base. Remove spark plugs.
3. Connect CYLINDER COMPRESSION GAUGE (Part No. HD-33223-1) to front cylinder.
4. Make sure transmission is in neutral. With throttle plate in wide open position, crank engine continuously through 57 full compression strokes.
5. Note gauge readings at the end of the first and last compression strokes. Record test results.
6. Connect the gauge to the rear cylinder and repeat test.
a. Compression is normal if final readings are within specification and do not indicate more than a 10 psi (0.689 bar) variance between cylinders. Refer to Table 3-22.
b. Compression is below specification if the readings are 100 psi (6.89 bar) for 883 cc engines or 150 psi (10.3 bar) for 1200 cc engines. Refer to Table 3-23.
7. Inject approximately 1/2 oz (15 mL) SAE 30 engine oil into each cylinder and repeat the compression tests on both cylinders. Readings that are considerably higher during the second test indicate worn piston rings.
Note. Verify throttle plate is in the closed position after testing.
Table 3-22. Normal compression ranges
| ENGINE | COMPRESSION | |
| psi | bar | |
| XL 883 | 165-180 | 11.4-12.4 |
| XL 1200 | 200-225 | 13.8-15.5 |
| XR 1200X | 170-185 | 11.7-12.8 |
Table 3-23. Compression test results
| TEST RESULTS | CAUSE |
| Compression low on first stroke, builds up on the following strokes, but does not reach normal. Improves when oil is added to cylinder. | Ring trouble |
| Compression low on first stroke, does not build up on following strokes. Does not improve with the addition of oil. | Valve trouble |
| Head gasket leak | |
| Incorrect pushrod length |