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Fuel system

Fuel tap

Opens, closes or sets the fuel supply to reserve (carburettor models).

How it works

The fuel tap selects ON / OFF / RES (reserve). Many are vacuum-operated: they only let fuel through while the engine is running. If it fails, the bowl runs dry and the bike stalls after starting, or fuel stops flowing altogether.

Maintenance tips

  • If in doubt, try the PRI position (if fitted).
  • A tap that leaks or no longer shuts off should be replaced.

Related symptoms

⚠️ The information on this page is provided for educational purposes to help you understand the role and operation of the part. It replaces neither a physical inspection nor the judgment of a certified mechanic. Before any work on a safety-critical component (braking, steering, transmission, suspension), have the part's condition confirmed by a professional.

Fuel tap · MotoDiagnostic