Performance AC CDI (No Rev Limiter) - GY6 50cc (139QMB) (Standard)

High-Performance CDI for GY6 Scooters, 50cc to 170cc

This performance AC CDI is built for GY6-style scooters with engines between 50cc and 170cc and is meant to take the place of the factory unit. It uses an aggressive ignition curve and removes the rev limiter, letting the engine reach higher RPM. It is a useful option among GY6 50cc scooter parts for riders who want to tune their machine.

Rev Limiter Removal and Ignition Timing

The ignition timing map on this CDI has been retuned to improve acceleration and throttle response. Because the factory RPM cap is gone, the engine can rev further, which can noticeably change how it performs. Output runs at 400–600 volts, giving a strong spark for more complete combustion.

Billet Aluminum Housing Design

An orange billet aluminum case encloses the unit and also helps draw heat away from the internal transformer. The housing guards the delicate electronics against vibration and heat, which supports dependable operation under hard use.

Specifications

• Connector: 6-Pin (Square 2-pin + 4-pin block)
• Ignition Type: AC (Alternating Current)
• Voltage Output: 400–600V
• Manufacturer: ISO 9001 Certified

Fitment

This CDI works with a range of GY6 engines, including:

• 50cc / 80cc: 139QMA, 139QMB, 1P39QMB, 1P39QMA-2, YN139QMB, JJ1P39QMB, 139FMA-2
• 125cc / 150cc / 170cc: 157QMJ, 161QMK, 152QMI, 1P61QMK, 1P57QMJ, 1P52FMI

If your engine code includes "QM" or "FM" and uses an AC CDI setup, this module will probably fit. It is not suitable for genuine 50cc scooters such as the Buddy, or for models running DC ignition, such as the Wolf Jet II.

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