Carb Stuff Explained

First, you can almost be guaranteed that if someone had a bike sitting in a garage for a period of time, that he/she did not start it on a regular basis to keep it in good running condition. Nor would the fuel tank have been completely filled or have a stabilizer added. The fact that the tank was not filled would allow for condensation to form in the tank. The inside of the tank would then begin to rust. Also, the fuel in the tank would tend to evaporate over a period of time and leave sludge on the bottom of the tank.

Likewise, fuel in the carbs and in the float bowls tend to evaporate and leave sludge as well as the carb having built up some varnish from whatever amount of time the bike had been stored.

Fuel in the fuel petcock will do about the same thing. Fuel in the fuel lines does so as well.

Some fuel may (at some time) have settled in the breather check valve, evaporated, and caused the ball in the check valve to stick.

So as the story goes…you buy this bike, start it up, it runs great and you ride off into the sunset.

The sludge in the fuel lines, float bowls and fuel tank now start to congregate in all of the orifices of the carbs. Rust starts to flake off the inside of the tank and add to the congestion. Varnish in the carbs begins to flake off and clogs the jets. The breather check valve won’t allow the tank to breath and causes a vacuum lock.

Add to this a couple of dried out vacuum lines which operate the diaphragm in the fuel petcock.