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My motorcycle engine is stalling when cold.

It's nice to be able to start the engine and let it warm up while you are putting your helmet on. So if your motorcycle tends to stall during warm up, it's rather annoying.

Please note that this page only covers fuel injected motorcycles. The older carburettor bikes can stall during the warm up phase for very different reasons.

What can make the motorcycle engine stall when it's warming up ?


During the warm up phase, the factories are allowed to run the engine on a richer mixture, so idle problems during warm up is rarely caused by too lean air/fuel ratio.
But there is several other problems that can cause the cold engine to stall.

- "Choke" lever not engaged to raise the idle RPM (Only for early fuel injected motorcycles where you can adjust idle level during cold starts from the handle bar)
- Idle level set too low (Can be adjusted by the owner on some bikes)
- Leaking intake rubber hoses between throttle valve housing and cylinder head
- Throttle position sensor (TPS) not correctly adjusted
- Valve clearances are too tight
- Low compression.
- Faulty water temperature sensor or oil temperature sensor