Amal-Type 600 900 Concentric Series Throttle Slide Return Spring(s) PN# 622/131 W

The throttle slide return spring is an important component in the Amal Concentric and Wassell Evolution carburetors as it returns the throttle slide to the resting position in the mixing chamber when the twist grip is rolled back during deceleration. This listing is for (1) spring.

This economically-priced return spring is a direct replacement for the Amal Concentric 600 and 900 series carburetors. Overall length is 3″, with an outside diameter of 5/8″.

The return spring is captured within the throttle slide body and the carburetor top cap. It provides the necessary tension to pull the relaxed throttle cable wire through the sheathing to allow the slide to safely return to its resting position. A weak or otherwise compromised spring can allow the slide to hang up in a worn or warped carburetor mixing chamber, resulting in a safety hazard while operating the motorcycle. Inherent friction in the throttle cable requires a strong return spring for proper operation of the carburetor.

Fitting the return spring is a simple but challenging procedure that usually involves using a needle-nosed pliers to lever the spring into compression by slightly gripping the throttle cable. Once the spring is sufficiently compressed, the throttle cable can be released from the slide and the needle and clip assembly can be removed whilst holding the compressed spring out of the way. The spring can then be withdrawn, with installation of the return spring in reverse order of removal.