Keihin Specs

Carburetors regulate fuel flow on motorcycles.

Carburetors are an important component in gasoline powered engines, mixing fuel vapor and air to create efficient combustion, which converts to mechanical power. Motorcycle carburetors come in a multitude of options, designed for street, off-road, casual ride and racing. Keihin offers five lines of carburetors for every motorcycle engine model and type. Keihin carburetors cover the gamut, from inexpensive bolt-on designs, enhancing handle and performance of motor-cross dirt bikes, to full-throttle super-charged carburetors, used for high-performance super-bike racing.


Keihin FCR Carburetor models 33MM, 35MM, 37MM, 39MM and 41MM are all engineered with a durable and dependable flat valve, air brake acceleration air pump. The flat valve and slide are hard-coated and engineered to run clean on rollers, for a smooth ride. This is the perfect enhancement or replacement part for all four-stroke engines.


Keihin PWK Carburetor models 28MM and 29MM are 83 mm by 147.4 mm in size. The 33MM and 35MM units measure 91-mm by 164.3-mm. The larger PWK models are 36MM, 38MM, and 39MM. These are designed with a width of 91 mm by 171.6 mm in height. The PWK carburetors are designed with a semi-elliptical section valve, providing riders with enhanced air flow. The PWK is a more powerful carburetor than the FCR, providing riders with more rapid engine revs on top, without letting the engine go flat.


Keihin PE Carburetors models 20MM through 28MM are 83 mm in width, ranging from 136 mm to 150.9 mm in height. Keihin PE models 30MM through 38MM are each 95 mm in width, ranging from 157.8 mm to 182.5 mm in height. These PE carburetors are designed with a chrome-plated round slide valve for two-stroke engines. they are an inexpensive bolt-on carburetor designed to increase performance and ride on mini-cross dirt bikes and scooters.


The Keihin PWM Carburetors are Keihin’s top performer. The PWM is available in three models: 38MM, 39MM and 40MM. Each measures 75 mm in width by 154.5 mm in height. This high performance carburetor was designed with a shorter length, giving the throttle an unparalleled response on top end cycles. The larger float bowl and quad vent system allows two-stroke engines great air flow, enabling them to run in the worst conditions. Keihin PWM carburetors are ideal for fast and furious motor-cross and street-racing bikes.

FCR Street:

Keihin FCR Street Carburetors, available in 32MM, 33MM, 35MM, 39MM and 41MM models, all come in a wide-range of horizontal and downdraft styles and options for two, three and four-cylinder engines. Keihin FCR street carburetors are used by super-bike racing teams around the world. These high performance carburetors are available for application to any road racing bike.