Throttle valve free play removal kit for Keihin FCR MX carburetors.

After many hours of usage, the throttle valve wheels may have worn out the carburetor by creating grooves in the body. This creates “free play” (forward – backward) on the throttle valve and, once that free play becomes too much, air will get past the sides of the throttle valve (instead of underneath it). This results in bad throttle response, unstable behaviour and an overall poor performance.

This kit contains 2 inserts and 1 bearing. Materials choice is highly critical, as the inserts need to be mechanically and chemically stable (fuel resistant), in harsh conditions for an extended period of time. The bearing is from SKF. Installation is easy: The throttle valve wheels are to be discarded, the new bearing is installed on the throttle valve (where there is no bearing), the inserts are placed over the bearings and the complete unit (throttle valve + inserts) is inserted into the carburetor. The free play will be back to factory spec, adding many more years to your carburetor lifespan. As a bonus, throttle actuation will become extremely light and smooth.

This kit fits: 37-41mm. Keihin FCR MX carburetors.
You will get: 2 inserts + 1 bearing.

note: on FCR MX carburetors with a removable cable bracket, a corner of the bracket has to be trimmed; detailed instructions will soon be available.

Installation instructions and images will be available soon.

Complete as pictured.