# Idle speed

> Idle speed is the lowest engine speed at which the engine keeps running with the throttle closed.

- **Also known as:** Rölanti devri, Idle, Relanti
- **Turkish term:** Rölanti
- **Category:** [Carburettors & Parts](https://motorsikletparcasi.com/en/category/carburettors-and-parts)
- **Page:** https://motorsikletparcasi.com/en/glossary/idle-speed

The correct idle speed is given in the owner's manual; on most motorcycles and scooters it is between 1,000 and 2,000 rpm. On carburettor engines it is set with the idle screw; on fuel-injected engines the ECU controls it automatically.

## Common causes of a hunting or low idle

- An air leak at the intake manifold
- A dirty [carburettor](https://motorsikletparcasi.com/en/glossary/carburettor) pilot jet or [throttle body](https://motorsikletparcasi.com/en/glossary/throttle-body)
- A worn [spark plug](https://motorsikletparcasi.com/en/glossary/spark-plug) or clogged [air filter](https://motorsikletparcasi.com/en/glossary/air-filter)
- Incorrect [valve clearances](https://motorsikletparcasi.com/en/glossary/valve-clearance)

## Related terms

- [Carburettor](https://motorsikletparcasi.com/en/glossary/carburettor): A carburettor is the mechanical fuel system component that mixes petrol into the incoming air in the correct proportion.
- [Throttle body](https://motorsikletparcasi.com/en/glossary/throttle-body): The throttle body controls how much air enters a fuel-injected engine using a butterfly valve linked to the twist grip.
- [Engine speed (rpm)](https://motorsikletparcasi.com/en/glossary/rpm): Engine speed is the number of crankshaft revolutions per minute (rpm), shown on the tachometer.
- [Valve clearance](https://motorsikletparcasi.com/en/glossary/valve-clearance): Valve clearance adjustment sets the gap between the valve stem and the part that opens it (rocker or bucket) to the value in the manual.

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- Source page: https://motorsikletparcasi.com/en/glossary/idle-speed
- Last updated: 2026-10-09
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