Raleigh_TA wrote on 12/31/69 at 16:00:09:


The petc0ck has a "vacuum" switch.  The engine creates vacuum (sucking...).  The carb steals a little of that vacuum to run the switch.  The switch is a piece of rubber that has a spring on one side and on the other is a piece of metal that seats against the opening going to the gas tank.  The rubber "diaphragm" acts like a seal to keep the gas from going into the carb at a spot it shouldn't.    It works when the engine runs, the vacuum going into the back of the petc0ck spring side, and pulls it back and the metal comes away from the opening to the tank , gas flows. Shut down the engine, the sucking is gone so the spring pushes the metal thing back and closes down the flow.

Why does it go bad......it's moving.......and new gas has additives that could attack the rubber.

#4 will leak as it is subject to pressurized oil. It is easy for it to slip  out of the groove on reassembly and get cut or pinched and leak. My have all leaked on start up while on the rack so were easy to redo. I order the o-rings 6 at time so I always have them for oil changes or changing the oil after an unexpected repair. I've found that many of the o-rings used by both Suzuki and Kawasaki are not in my $50.00 metric assortment for whateve reason. I do have better luck going to the assortment when working on Honda's. If the bike has been drained and is now cooled off enough, some stout grease in the groove helps to hold the 0-ring in position until clamped in place. Max

A suggestion, before you spend alot of time to R & R that heat shield as it is a terror. Use a flashight and mirror to see if it is just residual oil burning off. Black sooty plug is too much fuel for the amount of air, high fuel level, jet fell out of place, idle mixture screw too far open, air bleeds plugged in carb, air flilter plugged or liquid soaked, If you are running that sooty, may even be unburned fuel collecting in the low spot of the pipe to muffler attachment and soaking that gasket and burning off. Max