Rough idling, leakage at the flange or a piston that won't drop back down are classic signs of a tired SU HS6 on the twin-carburetor B18B in early 140s. This category gathers the wear parts and adjustment details that belong to that specific carburetor setup, so the rebuild can be done part by part instead of replacing the whole carburetor.
The group includes metering needles and jets that control the mixture, gaskets and washers that seal against air leaks, plus springs, spring washers, screws and retainers for mounting and the damper piston. During an overhaul, a worn metering needle and dry gaskets are the most common things to check – both cause lean or leaking running behaviour. Because the B18B ran twin carburettors, needles and jets should be matched equally in both carburettors for even running.