Triumph T140 (Bonneville 750) Oil pressure Sensor Warning Switch 

The Triumph T140 (Bonneville 750) uses a low oil pressure warning switch that is typically located near the crankcase, often on the timing cover or near the oil pump. Here’s some key information regarding the oil pressure sensor and related pressure values:

Oil Pressure Sensor Details:

• The oil pressure sensor is a simple on/off switch that illuminates the oil warning light if the pressure drops below a set threshold.
• The typical activation pressure for the warning light is 3-7 psi (0.2-0.5 bar).
• If the oil pressure drops below this level, the sensor completes the circuit and turns on the warning light.

Typical Oil Pressure Values for the Triumph T140:

• Cold Idle: 50-70 psi (3.5-4.8 bar)
• Hot Idle: 10-20 psi (0.7-1.4 bar)
• Running at 4000 RPM (Hot): 40-60 psi (2.8-4.1 bar)

Troubleshooting Oil Pressure Issues:

1. Oil Light Stays On at Idle – If the oil pressure light stays on when idling but goes off when revving, this may be normal for a hot engine, but it’s worth checking the oil level and viscosity.
2. Light Stays On Constantly – This could indicate:
   • A faulty sensor
   • Low oil level or thinning oil
   • A clogged oil filter or strainer
   • Excessive engine wear (e.g., worn crankshaft bearings or oil pump)
3. Intermittent Light Flickering – Loose wiring, bad connection, or minor pressure fluctuations.

Replacement and Testing:

• The oil pressure switch for the T140 is generally a 1/8 x27 tpi American pipe thread (check your specific model).
• To test, you can use an oil pressure gauge by temporarily removing the sensor and fitting a manual gauge.
• If replacing the sensor, use Teflon tape or thread sealant to prevent leaks.

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