Check the engine oil level

A four-stroke engine keeps its oil in the bottom of the engine (the sump) and uses it again and again. Too little oil wears and seizes the engine. Too much oil can blow out through seals and the breather. Check the level every week, before a long trip and after any leak. Two-stroke bikes with oil injection have a separate oil tank; check that tank instead (see the last section).

Safety

• The exhaust and engine are hot after running. Keep hands and sleeves away from the pipe.
• Do not check the level with the engine running.
• Wipe up spilled oil at once. Oil on the tyre or the floor makes you slip.

You need

• A clean rag and good light.
• Oil of the grade and type named in your manual or on the filler cap. A bike with a wet clutch (clutch in the engine oil) needs motorcycle oil made for wet clutches; car oil marked "energy conserving" can make the clutch slip.

Steps

1. Park on flat, level ground. Hold the bike upright or put it on the centre stand. A bike leaning on the side stand gives a false low reading.
2. Start the engine and let it idle for a short time: 2 to 3 min (K-Light 125). This fills the oil passages.
3. Stop the engine and wait: 2 to 3 min (K-Light 125) so the oil drains back into the sump.
4. Find the dipstick (it is usually part of the filler cap on the right side) or the sight glass (a small round window low on the engine cover).
5. Dipstick: unscrew it, wipe it clean and put it back in the hole. On the K-Light, do not screw it in when you check; just rest it on the threads. Other bikes may say to screw it in; follow your manual.
6. Pull the dipstick out and read where the oil reaches between the upper and lower marks.
7. Sight glass: read the oil line against the upper and lower marks in the window.
8. If the level is near the lower mark, add a little oil through the filler hole, wait one minute and check again. Stop at the upper mark.
9. Look at the oil on the dipstick. Note the colour and smell. Milky, frothy or petrol-smelling oil is a fault; see the links below.
10. Refit the cap firmly by hand.

Check your work

• The oil line sits between the marks, closer to the upper mark.
• The cap is tight and there are no drips around it.
• You wrote down the date and the distance. A fall between checks tells you about oil use.

Two-stroke oil tank

• On a bike with oil injection (autolube), the oil for burning is in a separate tank, often under the seat or a side cover. Keep it above the low mark or the warning line. If it runs dry, the engine can seize.
• The gearbox on a two-stroke has its own oil. Check it at the level screw or dipstick as your manual shows.
• A two-stroke has no oil filter and no oil pump for the crankcase. The gearbox oil is splashed around and still needs changing at the interval in the manual: Change the gearbox oil on a two-stroke.
• Small utility engines with no dipstick or plug are filled to the threads of the filler hole: Check the oil on a small engine without a level plug.
• Some engines settle at their own level. If the level sits a little low and stays there, check often over several rides to see whether the engine is using oil or finding its level.

If it did not fix the problem

• Level falls every week and there is no puddle: Oil level drops but there is no visible leak.
• Level is above the upper mark or rising: Too much oil in the engine or Oil smells of petrol or the level rises.
• Oil looks like milky coffee: Oil is milky or creamy.
• Oil warning light stays on with a correct level: Oil pressure or oil level light is on.

Reference values (K-Light 125)