Motorcycle Glossary
CDI (capacitor discharge ignition)
In Turkish: CDI
In short
A CDI (capacitor discharge ignition) unit stores energy in a capacitor and dumps it into the ignition coil to create the spark at the spark plug.
The CDI sets the spark timing (advance) from the signal of the pickup coil, which reads a trigger lug on the flywheel. There are two main types:
- AC CDI: powered directly by the stator.
- DC CDI: powered by the battery; a weak battery means a weak spark.
Symptoms of a problem
- No spark at all
- Cutting out or misfiring at a particular rpm
- Stalling when hot and restarting when cool
Before replacing the CDI, check the spark plug, ignition coil, pickup and wiring connections.
Also known as (including Turkish names)
- Ateşleme beyni
- CDI ünitesi
- Capacitor Discharge Ignition
Related products
CDI Units & Ignition Coils
Last updated: October 9, 2026
