I've learned something new about Webers!

[OliverSedlacek]

Like most owners running a brace of Webers, I disconnected the cold running (choke) mechanism and fitted blanking plates to save weight. You can buy them off Weber, but I made my own. Earlier this year I had a lot of problems with poor running, and I eventually diagnosed the problem. A backfire in the induction system would push the cold start valves up their bores against some weak springs. This gives rises to plenty of pops and bangs, which we call 'character' in old engines. Eventually however the bits all get a bit out of shape, and one or more valves stick at the end of their travel, leading to very poor idling and sooted up plugs. The cure is not to rely on the weak return springs, and to restrain the valves with pins protruding from the blanking plates (in a similar manner to the original actuating levers). Problem solved, with a bit less popping and banging.