The HW-11B is an updated version of the HW-11A with metric thread on the adjustment jets to de-sensitive the setting, and is fitted with the half shaft butterfly system which is improving the engine throttle response.

  • Avenger Class Venturi/Body Design
  • Avenger Class Inlet Needle and Seat Design
  • Avenger Class Idle/Acceleration Nozzle Design
  • Avenger Class Acceleration Fuel Circuit Design
  • Easy-Adjust High and Low Needle

Easy-Adjust Feature:

The HW-11B uses different adjustment needles than the HW-11A. These Easy Adjust needles desensitizes adjustment, making it easier to find the proper setting . This carburetor is homologated by the CIK for KF2 races.


Replaces HW-11A.

Can also be used to upgrade an HL carburettor with similar size venturi and throttle bore (but check your local race regulations to be sure the carburettor model is not mandated).

Has also been used on Yamaha KT100 engines but requires a manifold.

Can also be used with 4-stroke engines if modified for pulse hole.

Carburetor Settings

Engines vary by manufacturer, manufacture date and tuning. For optimum performance, you might need to try different settings. Below is the factory setting. Adjust first the High then the Low needle each in 1 minute increments (you should not need to adjust more than 10 minutes in normal conditions, but more in extreme conditions like hot or rainy weather).

Yamaha KT100 (User reported)

L = 1 5/8  H = 7/8

Repair kit and Diaphragm Gasket for the carburetor:

Main: RK 1 HW and DG 1 HW

Optional: RK 2 HW and DG 2 HW

Weight1 kg
Venturi Diameter


Throttle Bore Diameter


L=1 Turn

50 minutes (1' 50")

H=1 Turn

40 minutes (1' 40")

Opening Pressure

0.65 bar

Closing Pressure

0.55 bar

Throttle Bore Range

Racing Class

Product Line


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