Cvk Main Jet (# 140) for Scooters & Mopeds

CVK Main Jet (#140) for 139QMB and GY6 Scooters and Mopeds

This CVK Main Jet (#140) is made for 139QMB and GY6 scooters and mopeds. It helps regulate the fuel mixture so the engine runs efficiently. It works with a range of CVK carburetors that have a 5mm main jet opening. You can find more options in our scooter carburetors and jets range.

Jetting and Performance

Getting the jetting right usually takes some testing, since it has a direct effect on how the engine performs. This main jet supplies the correct fuel-air ratio for smooth engine operation. Depending on how you ride and the conditions you ride in, you may need to make small adjustments.

Construction and Fit

This main jet has a Keihin round-style body and an M5x0.80 thread. It measures 8mm overall, so it suits the many scooter models that use a 5mm main jet opening. Install it carefully and make sure it is seated securely in the carburetor for best results.

Specifications

• Thread Size: M5x0.80
• Overall Length: 8mm
• Fits: 139QMB-based 50cc/80cc GY6 engines and 157QMJ-based 125cc/150cc/169cc engines with a 5mm main jet slot CVK

Fitment

Fits:

• 139QMB-based 50cc/80cc engines (codes 139QMA, 139QMB, 1P39QMB, 1P39QMA-2, YN139QMB, JJ1P39QMB, 139FMA-2, BD1P39QMB, BN139QMB, 147QMD, other QMA and QMB)
• 157QMJ-based 125cc/150cc/169cc engines (codes 157QMJ, 161QMK, 152QMI, 1P61QMK, YN1P57QMJ, 1P52FMI, 154FMI, JJ157QMJ, 1P57QMJ, BN157QMJ, BN161QMK-A, other QMJ, QMK and QMI)
• Other GY6 engines with a 5mm main jet slot CVK carburetor and an engine code containing QM or FM

How to choose: Confirm the carburetor's main jet slot is 5mm and the thread is M5x0.80. The jet is 8mm long and has a Keihin round-style head.

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