Motorcycle Fuel Petcock Positions

Vacuum petcocks are less important for this discussion since they are usually left in the run position and are opened and closed automatically by the engine vacuum of.

Motorcycle fuel petcock positions. The normal run tube rises about 35mm from the bottom of the tank. A motorcycle fuel petcock is a fuel valve which the rider can use to shut off or turn on the flow of gasoline from the fuel tank into the carburetor. It may have been changed since these valves were notorious for problems.

You can find a pdf in google if you do a search or you can ride around with the petcock in all 3 positions with a small gas can on the back and find out. Most older motorcycles have a three-position fuel petcock valve known as a petrol tap in the UK mounted on or nearby the fuel tank to control the supply of gasoline. Hidden behind the lever in the pic Use Primary when you want to start and operate it.

When the engine is started the vacuum from the engine is supplied to a diaphragm on the backside of the petcock open the fuel valve. A petcock or sometimes referred to as a fuel tap or fuel valve is a 2 or 3 way valve on the bottom of your fuel tank. Turn the fuel off.

Petcocks fasten to the tank by both right hand and left hand threads. This is the on position. Your o-ring is part of the fuel screen assembly.

Switch to reserve when you run out of fuel. My yam has an onoff mark right on the petcock. Fuel is pulled by either gravity or vacuum from the fuel system.

The fuel petcock is vacuum operated in the ON and RES positions. The reserve position accesses the bottom portion of the fuel tank. Pri primary res reserve off closed no flow.