What Position Should My Petcock Be In? 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: on, off, and reserve.
The reserve position accesses the bottom portion of the fuel tank.
Which way is on for a Petcock? You are in the “ON” position. Counter clockwise is “OFF”. Clockwise is “RESERVE”. Check it by turning to the off position and pull off the gas line.
Should Turn Petcock off? No, there is no legal requirement that you should turn the petcock to “OFF” when you shut your bike down at the end of your ride.
However, it is a good practice, especially if you own an older motorcycle (1990s vintage or earlier), before gravity-fed carburetors were largely replaced with fuel injection systems.
How do I know if my Petcock is bad? Symptoms of a bad vacuum fuel pump/fuel petcock:
What Position Should My Petcock Be In? – Related Questions
Can you bypass a Petcock?
Yes you can just run a hose from the tank to the carb and plug off the vacuum line. Only problem is that the bowel of the carb may over fill when it is just sitting, but probably not. It is easy enough to check out and see, if it does not work out just put it back together as it was.
Is a Petcock necessary?
The petcocks purpose is to prevent fuel flow from the fuel tank to the motorcycles carburetors. They have this in part because motorcycles spend a large chunk of their lives parked on a sidestand. And the petcocks prevent the fuel from overloading the float seals on the “downhill” side of the bike.
How does vacuum Petcock work?
The way a vacuum petcock works is the vacuum pulls the diaphragm back, compressing a spring and releasing pressure on a ball or some other sort of valve, this allows fuel to flow around the ball and to the carb. When the engine shuts off, the vacuum is removed and the fuel shuts off.
Why is it called a Petcock?
The “pet” part seems to be rooted in an old sense of “pet” meaning “small,” possibly related to our modern “petty,” in turn harking back to the French “petit” (small), which all makes sense since a “petcock” is, as we noted, a small faucet.
How does a reserve fuel tank work?
In motorcycles and cars, the fuel reserve setting indicates that the level of fuel in the tank is low. When the main fuel is exhausted, the motor will start sputtering, prompting the rider to change the position knob to continue riding with a known smaller quantity of fuel.
What does a Petcock do?
A petcock is a small shut-off valve used to control the flow of liquid or gas.
Historically, petcocks were threaded valves controlled by a butterfly handle; modern petcocks are typically ball valves.
What does PRI mean on a Petcock?
Here’s the word from that listing. The pet cock on the 800 drifter has 3 positions… PRI (Prime); RES (Reserve) and ON. This is a vacuum operated valve so when the bike is off, the valve is automatically OFF. Use the PRI position only to prime the valve after maintenance, etc.
What happens if you leave the choke on overnight?
Leaving the choke on for too long will cause unnecessary engine wear and waste fuel. The engine needs its fuel to be vaporised in order to burn it. This is done by the carburettor where the fuel is mixed with clean air coming from the air filter, and sent into the pistons to be ignited.
What can a bad Petcock cause?
It’s the float that controls how much fuel gets into the float bowl. However, if the petcock is not shutting the fuel off it could cause the carb to overflow while hauling your bike on a trailer as the float bounces around and lets the bowl fill more than it would sitting still.
How do you fix a clogged Petcock?
If there are two little screws holding a metal plate on the front of the petcock, loosen them before unscrewing the petcock from the gas tank. Pull the selector knob off. Using something pointy, gentle pry the four holed rubber grommet out of the petcock. Wash the petcock out with clean gasoline.
Why is my Petcock leaking?
At worst, fuel fills the cylinder, eliminates compression and prevents the piston from moving. Once the petcock is “off” you’ll notice gas leaking out of the face of the petcock. That’s when you know it’s the petcock and not anything else associated with the fuel system.
How do I know if my scooter fuel pump is bad?
The first and most common symptom of a bad fuel pump that you should notice is a whining noise from the gas tank. This symptom can almost always be attributed to the fuel pump. A whining fuel pump is a sign that the fuel pump is wearing out and should be replaced.
Does a scooter have a fuel pump?
Scooter Fuel Sysytem 101!!
How does a diaphragm Petcock work?
The way a vacuum petcock works is the vacuum pulls the diaphragm back, compressing a spring and releasing pressure on a ball or some other sort of valve, this allows fuel to flow around the ball and to the carb.
What does a Petcock do on a scooter?
Most scooters use a vacuum actuated petcock. That means fuel flows from the fuel tank to the carburetor only when the engine is cranking or running. To test the petcock, disconnect the fuel line from the carburetor.
Can a fuel Petcock go bad?
If the bike runs on RES and PRI but has issues running in ON,then the petcock is bad. If you disassemble the petcock,you will more than likely damage the internal diaphragm.
What will happen if we run the bike in reserve mode when the tank is full?
Running on the reserve tank will give you the miles offered by that tank until you run out of gas. If you run the reserve tank out, the bike will stop. Todays bikes have one tank which incorporates a petcock which can be switched between two levels of available fuel, normal and reserve.
