Automatic fuel taps arrived early on for Suzuki and the company made substantial marketing capitol about their fitment. More of a consumer convenience than genuine improvement, the tap remains in the ON position but blocks the fuel flow until the engine’s vacuum pulls a spring loaded diaphragm away from the outlet pipe. The required vacuum is fairly minimal and easily created even by kick-starting an engine. These taps tend to work fine until wear, fuel or old age takes out the seals and diaphragms. Repair kits are available for some vac taps but not others. If you are going to attempt a repair on one of these units pop some register marks on the sealing back plate and the tap body to ensure everything goes back together in the correct position. Also note and photograph the orientation of the diaphragm, the spring and seals. Finally note that the back of the diaphragm is actually vented to atmosphere via a tiny channel in the casting. Without this the tap would flow for a period after the engine was turned off rather than cutting out immediately.