Gearbox and Clutch

With over 40 years of experience, we offer high-quality gearbox rebuilds for your unit twin models with the four and five-speed types.

We strip and assess the gearboxes to produce an estimate for the work and parts required. We itemise all the costs, so you know exactly what we’re doing. We will replace worn gears, sleeve gear bushes and kick-start ratchet gear bush on the main shaft.

In addition to our portfolio of high quality parts, we offer a range of services to rebuild and renovate your clutch and primary chain.

We advise using modern friction material in the clutch plates and fitting the SRM clutch pressure plate conversion (available in our online shop). The conversion will improve the engagement and release of the clutch.

The SRM clutch pressure plate conversion is available for BSA A7/A10, A50/A65, Pre-Unit B31, B33, Goldstar, Triumph T120/T140, Pre-Unit T100, T110, T120, Unit 3TA, 5TA, T100.

A complete conversion to replace the 6-spring clutch, giving you light operation, an excellent feel and positive action. It also allows easy selection of neutral at a standstill without any drag or crunch.

Swinging arm models only

A range of services to repair and restore the A7/A10 clutches.

It’s common to find wear in the main and lay-shaft bushes and shafts on the A7/A10 clutches. We can reground them to restore the bearing surface, make new bushes to size, and fit them to the casings.

Our hydraulic clutch conversion solves your heavy-clutch action, cable resistance and cable routing problems.

Our hydraulic clutch conversion provides a light clutch action and is maintenance-free for your convenience. The modification works by replacing the cable-operated three-ball clutch lifter with a hydraulic slave cylinder and pusher. The clutch slave cylinder mounts with existing fasteners, and the adaptor replaces the standard cable adjuster.

A Primary belt drive conversion is available.

Based around the NEB alloy clutch, we modify the front steel pulley to accept the original cush drive assembly. Primary belt drives can suffer from feeling “harsh” in high gears at low speed. The addition of the cush drive will take out the shock loading. You will need to supply the original cush drive assembly.

We use a range of techniques to replicate the original finish of the gearboxes and clutch.