Liquid vs air cooling: what to check on each

The cooling type decides what you inspect in the garage. November is a good moment to check the system after summer loads, before cold weather brings surprises.

• Check the owner's manual to see whether your bike is liquid-cooled, air-cooled or oil-air cooled. Everything else depends on it.
• On a liquid-cooled bike, check the coolant level in the expansion tank on a cold engine: it should sit between min and max. Coolant type and replacement interval are in the manual.
• Inspect the radiator and hoses for cracks, swelling, leak traces, and dirt or leaves clogging the core. Clean gently with a water jet from the back side, without bending the fins.
• On an air-cooled engine, look over the cylinder fins: dirt between them and damaged fins reduce heat dissipation. Oil level and condition matter doubly here, since oil also cools the engine.
• Never open anything on a hot engine: the system is pressurised and the coolant will scald. If coolant vanishes with no visible leak, or you see steam or white residue, go to a workshop.