TThrottle valve no.4 Hard Anodised. The latest upgrade for 600 Series Mark 1 Concentric carburetters from the Amal Carburetter Company are precision made forged aluminium throttle slides with a high quality hard anodised surface finish that offers superb resistance to wear and smoother throttle operation.

The slides are fully interchangeable with existing slides with the same range of cutaways available. The slide has been re-designed to improve rigidity and robustness while retaining the efficiency of the original