What should you do before you check the level of oil in the engine?

In the photo you can see a motorcycle engine with the oil filler cap in the clutch cover. Before checking the oil level, you switch off the engine and wait a few minutes - answer C.

The Road Traffic Act requires a vehicle to be kept in a condition that does not endanger safety, and the correct oil level is a condition for the engine to survive. While the engine is running, the oil circulates through the whole engine - it is in the channels, on the shafts and in the cylinder head - and its level in the sump is too low. Measuring with the engine running (answer B) would show a lack of oil and lead you to overfill it, and too much oil does as much harm as too little: it leaks through the seals, floods the air filter and damages the clutch. That is why you switch off the engine and wait a few minutes for the oil to flow down into the sump, and you keep the motorcycle upright - on the centre stand or holding it straight, because on the side stand (answer A) the motorcycle is leaning and the sight glass or dipstick shows a false level. You check it according to the manufacturer's instructions: some say to measure when the engine is cold, others after warming up and waiting, but always with the engine switched off and the motorcycle upright.

Legal basis: Art. 66 para. 1 point 1 of the Road Traffic Act (Prawo o ruchu drogowym)