Triumph Norton BSA Amal-Type Concentric Mixture Screw (1) PN# 622/076

Description

The tapered mixture screw is important as it meters the fuel and air mixture in the idle circuit of the carburetor. The taper must be accurately shaped to provide a precision adjustment.

This Amal mixture screw as universal fitment to all years, makes and models of motorbikes that are fitted with 600 and 900 series carburetors.

The mixture screw is a specially tapered screw to fit into the tapered bore of the carburetor, allowing a precision air/fuel mixture to be metered through the pilot jet. Supplied with the o-ring fitted.

The screw maintains the idle circuit, and the o-ring seals the threads and prevents the screw from changing it’s established position in the bore.

The mixture screw is installed in the port by lightly threading it in until it bottoms out, then it is backed out 1-1/2 turns as a starting point in the carburetor tuning process