Motorcycle Repair: Bill, a question about the..., bill silver, air leak

Question
Bill,  a question about the honda cl125a.  The base of the carb, where it bolts onto the intake manifold, should be flat shouldn't it?  My carb has a slight bow to it and I suspect that's where I have an air leak.  Thanks.

Answer
Gary, the carburetor material is rather malleable and will warp when the retaining nuts are cranked down too hard. The O-ring in the carb base seals the connection between the carb and head/insulator.

The best course of action is to gently file the flange until it is flat again, then install a new O-ring. When you install the carburetor, just snug the nuts up gently, rather than try to cinch them down until the carb body meets the insulator/head. The tension on the O-ring will be sufficient to keep the nuts from loosening. Just check them every so often, as the O-ring will eventually compress and the connection will loosen a bit.

Make sure that the valves are set correctly and that the ignition timing is correct, as well. This will ensure that your carburetor settings will work, as specified.

Bill Silver