Radiator

How it works

The radiator gets rid of engine heat on liquid-cooled bikes. Coolant flows through the engine, heats up, then passes through the radiator, where thin fins with air flowing through cool it down. When stopped or at low speed, an electric fan takes over. The system is pressurised by the calibrated radiator cap, which raises the coolant's boiling point. Mounted at the front, the radiator takes insects, stones and mud: blocked or flattened fins reduce cooling and the bike runs hot. A stone can also puncture a tube and cause a leak. Inside, old coolant or tap water encourages scale and corrosion. A protective grille limits damage. Clean the radiator with low-pressure water, against the direction of airflow; a leak rarely repairs durably and usually means replacement.

Maintenance tips

• ✓Inspect and clean the fins with low-pressure water, from back to front; gently straighten flattened fins.
• ✓A radiator guard prevents stone punctures.
• ✓Never open the radiator cap on a hot engine: pressurised coolant can cause serious burns.
• ✓Change the coolant at the interval in the manual, using coolant suited to aluminium engines.
• ✓A falling level with no visible leak can come from the head gasket: have it checked.