Operation
See Figure 4-3. The red OIL PRESSURE indicator lamp illuminates to indicate improper circulation of the engine oil. The indicator illuminates when the ignition is turned on (before the engine is started), but normally extinguishes once the engine is running.
Notice: If the oil pressure indicator lamp remains lit, always check the oil supply first. If the oil supply is normal and the lamp is still lit, stop the engine at once and do not ride further until the trouble is located and the necessary repairs are made. Failure to do so may result in engine damage.
If the lamp remains illuminated, check the following:
- Low oil level
- Diluted oil supply or incorrect oil viscosity
- Faulty lamp wiring
- Faulty oil pressure switch
- Damaged oil pump
- Plugged oil filter element
- Inoperative or weak spring in the oil pressure relief valve
- Damaged or incorrectly installed O-rings in the engine
To troubleshoot the issue, always check the engine oil level first. If the oil level is within proper range, check oil pressure. See Troubleshooting of engine for oil pressure test.
Figure 4-3. Oil Pressure Indicator Lamp
Oil pressure check
| PART NUMBER | TOOL NAME |
| HD-45308 | OIL PRESSURE GAUGE |
| FASTENER | TORQUE VALUE | |
| Oil pressure test port plug | 10.0-12.0 Nm | 89-106 in·lbs |
1. Fill crankcase to proper level.
2. Figure 4-4. Remove plug.
3. Attach OIL PRESSURE GAUGE (Part # HD-45308) with appropriate adapter to oil pressure test port.
Note: After an engine rebuild, remove fuel pump fuse to verify that oil pressure is present before engine starts.
4. Test oil pressure.
- a. Run motorcycle until engine is at normal operating temperature.
- b. Record oil pressure on gauge.
- c. Stop engine.
- d. Compare oil pressure reading with specification. See Specifications of engine.
5. Remove test equipment.
6. Install plug. Tighten to 10.0-12.0 Nm (89-106 in·lbs).
Figure 4-4. Oil Pressure Test Port