Some bikes have an oil pressure light: it comes on when the oil pump is not making enough pressure. Others have an oil level light (the K-Light manual mentions an oil sensor alarm for level) or, on two-strokes, a light for the oil tank. All three should light for a moment at key-on as a bulb test and go out once the engine runs. A light that stays on or comes on while riding is a warning to stop. There is no single pressure value for all bikes; testing pressure needs the model manual and a gauge.
Is it safe to ride?
No. Stop the engine as soon as it is safe. Running without oil pressure can destroy the engine in minutes.
Quick checks first
- Stop and switch off.
- Check the oil level (four-stroke) or the oil tank (two-stroke).
- Look under the bike for a big oil loss.
- Does the light come on at key-on and go out after starting?
Diagnose it step by step
1Is the oil level below the lower mark, or the two-stroke tank empty?
- Yes: top up with the correct oil using Check the engine oil level. Look for a leak. If the light goes out at once after starting and there is no noise, ride gently and find out why the level was low. Two-stroke: go to Two-stroke oil tank level is not going down if the tank was full but the light was on.
- No, the level is correct: go to step 2.
2Is there a new knock, rattle or rumble?
- Yes: do not restart. Go to Deep knocking from the bottom of the engine.
- No: go to step 3.
3Does the light flicker only at hot idle and go out above idle?
- Yes: thin, old or wrong oil, or a worn pump. Change oil and clean the strainer with Change the engine oil and clean the strainer. If it continues, workshop.
- No, it stays on at all revs: go to step 4.
4Is the wire on the oil pressure or level switch disconnected, broken or rubbing on the frame?
- A wire touching earth turns the light on: repair it with Find a wiring fault.
- Wire good: go to step 5.
5Workshop: the oil pressure must be measured with a gauge in place of the switch, following the model manual.
- Pressure low: blocked strainer or centrifugal filter, worn oil pump, or blocked passage. The K-Light manual lists no or low pressure and a blocked oil passage as causes of seizure. See Assess bottom end and internal engine damage.
- Pressure correct: the switch is faulty; replace it.
What happens if you keep riding: the bearings and cam surfaces lose their oil film and wear or seize within minutes.
Causes, most likely first
| Cause | How to confirm | Fix |
|---|---|---|
| Low oil level | Dipstick | Check the engine oil level |
| Old, thin or wrong oil | Flickers at hot idle | Change the engine oil and clean the strainer |
| Wire to switch shorted to earth | Damaged wire | Find a wiring fault |
| Blocked strainer or filter | Workshop pressure test | Assess bottom end and internal engine damage |
| Worn oil pump | Low pressure | Assess bottom end and internal engine damage |
| Two-stroke oil tank empty or pump fault | Tank level | Check the two-stroke oil pump and lines |