Main Jets for PWK Carburetors – 21-28mm

High-quality main jets compatible with all 21–28mm PWK carburetors, including brands like Keihin, Stage6, Koso, Oko, Voca, and also Polini CP carburetors. Essential for precise and efficient carburetor tuning.

Jetting Tips

• Always start with a slightly larger main jet and decrease in 5-step increments until the engine runs smoothly.

• Test by running the scooter at full throttle briefly, then stop the engine and inspect the spark plug.

  • Black/oily plug: mixture too rich → decrease jet size

  • Whitish plug: mixture too lean → increase jet size (too lean may cause engine seizure)

  • Medium brown/reddish plug: mixture correct

Proper jetting ensures optimal engine performance, efficiency, and longevity.