BMW R65LS

Great engineering; German design – My BMW "boxer" 650 motorcycle has two Bing constant depression carburettors. I am familiar with all vrieties of the British Amal carburettors which are simple, robust and easily repairable. I am familiar with the old Zenith down-draught carburettor . I am familiar with the former constant depression carburettors fitted to BMC vehicles; these are easy to work with and robust. The BMW Bing carburettor was designed by someone demented. 1) It is overly complicated, which is just the start. 2) the float-needle lever has an extremely fine tolerance when it comes to the precise setting for ensuring fuel flow when the engine is running. And if the setting isn't correct the cylinder on which the carburettor sits either won't get petrol as the needle valve stays closed; or it won't close when the engine has stopped and the carburettor floods and drips petrol everywhere, which can also happen when the engine is running. I'd estimate the tolerance in adjustment of the float lever, a bendable piece of metal on the float, that has to be bent (adjusted) to get it right, is about 5 thou of an inch. 3) The air intake from the air filter box to the carburettor. Set this intake pipe, a curved bit of plastic pipe properly on the air intake port on the carburettor and when the carburettor is attached properly to the cylinder head the curved plastic pipe does not line up correctly with the air feed from the air-filter box.. The misfit is about 3/4 inch. Which entails brute force and bodging that should not be necessary.

Reminds me of my former vintage 1967 BMW 4 cylinder 2litre car; nice, but the damn silly design of the exhaust manifold meant that it took 1 1/2 hours and a second person and a crowbar to enable the 8 nuts to be undone from the studs to remove the exhaust manifold. I suppose I should have taken the engine out first. Good engineering is a waste of time if the design is demented.