1 1/8 MONOBLOC CARB 389 - 28mm - Jetting 300 main, 106 needle, #3 slide, #20 pilot

The Monobloc was the mainstay Amal design fitted across a long run of British twins before the Concentric took over, and this larger bore size shows up on the bigger-running setups. If you're rebuilding a bike that came with a 389-series carb, matching the body size and jetting here matters — swapping in the wrong needle or main jet changes how the bike runs at every part of the throttle.

We don't have this one tied to a specific model in our records, so before you order, check what your bike's parts book calls for and confirm the 389/18 is the right body and jetting combination for your application.