How do you test a moped Petcock?
Testing the petcock 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. Disconnect the vacuum line from the petcock.
What is vacuum petcock?
Here is a nice video on how a vacuum petcock works. The advantage to a vacuum petcock is that you can leave it in the “on” position when you shut the bike off and the vacuum operated valve in the petcock will close the fuel line when the bike is not running and the vacuum is absent.
What does Prime mean on a petcock?
PRI stands for PRIME. It allows the fuel to run freely without the engine running (as you found out with all the gas on the ground). It really should only be used if you are having vacuum problems. ON stands for on. It will allow fuel to flow when the engine is running by getting vacuum from the carb.
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.
Is the vacuum operated petcock on a VT worth it?
For the most part, the vacuum operated petcock on the VT & FT Ascots works well & usually doesn’t cause any problems. There is the potential of the diaphragm forming a leak & then not allowing enough fuel to flow to the carbs/engine, etc.
Why does it take so long to replace a petcock?
One possibility could be that the primary feed tube (petcock in the “on” position) is blocked. Now, you might say, “They replaced the petcock assembly” – and it took them more than two weeks! Really? HD’s vacuum operated petcock has two hoses (fuel and vacuum) and a nut that attaches it to the fuel tank.
Is the fuel supposed to shut off with a bad petcock?
If the petcock were faulty ie: bad diaphram isnt the fuel supposed to shut off? The purpose of the vac petcock is to close off the fuel when the engine stops from lack of vacuum. The restart is accomplished by the fuel in the float bowl until the engine draws vacuum and opens the petcock. More problems for some than they are worth.
Are there any problems with the HD mechanical petcock?
More problems for some than they are worth. Many have changed to a Pingle manual petcock or retro fitted to the regular HD mechanical petcock. Most times when they fail the engine just quits from lack of fuel. Glider has it right, get rid of the vacuum petcock and go for a Pingle.