S & S "B" Type Motorcycle Carburetor Tips


The old "B" S&S carburetor is a good carb, but many are getting old and in need of repair. There is only one "adjustment" per se, it's on the top of the carburetor. The little T-handle adjust the air-fuel mixture at idle only. Once you give it some gas, or are cruising it doesn't affect much.

There are low and high speed jets inside the carb, but if it's been running with these for years, chances are they are OK because they don't wear out or change. What does change is that air starts leaking in to the high vacuum areas around worn throttle shaft bushings or leaky manifold seals. Both these problems can be easily fixed, but must be addressed before the carburetor will work correctly.

If air is seeping past worn motorcycle parts, the tendency is to richen up the mixture at idle, or on the low speed jet to compensate, then the over-rich mixture fouls the plugs even though the motorcycle may spit or run lean. It's the worst of both worlds!

Another problem that happens with old S&S carburetors is that the float level is incorrect due to gas soaking into the foam float over many years. A high fuel level means an over-rich mixture and this too can foul plugs or give a bad stumble or flat-spot on accelleration.

Replacement floats are available and will fix this, though very early B-models will require an updated bowl/seat/needle to accomodate the new style float. Direct Parts, Inc. carries replacement motorcycle parts and rebuild kits for the B-model S&S. If you need instructions for an S&S carburetor, you can download a copy at www.sscycle.com . If it's a really old carb you might consider the new S&S Super E Carburetors. They are more compact so you have better leg clearance and incorporate an accelerator pump and improved starter enrichener circuit for better starting

Source: S&S.com