Petcock position question...

Okay, I'm going to get a reputation for asking stupid noob questions...

1. Which part of the petcock indicator "indicates" it's position? Does the handle pointed at "RES" mean it's on reserve or the rounded part?

2. I read somewhere that if the bike has been sitting for more than a few days since it last ran that it should be switched to "PRI" (prime) for a second or so to fill the carbs before you hit the starter. True?

3. If it's left on "PRI" when it's parked, fuel will continue to drip out of the air filters? True?

Every site has to have "one of those guys" that asks the dumb questions. I elect myself!

 

1) the end of the handle points to the position ( on my 650 it has a small arrow on the end, gotta look close though)

2) PRI is only used to refill the carb bowls, I've had my bike sit for days, even a week and not had to use PRI, some others do. SO its really your choice.

3) If left on PRI, AND your float needle or floats stick, then you can flood the crankcase or the airbox. If your floats are fine, then, in theory, you could leave it on PRi and have no problems, but thats a big IF. Thus, save thing is to NEVER leave your bike sitting on PRI.

Hope it helps, and P.s. they're not dumb questions, everybody has to learn and the only way is to ask

 

Another problem with leaving on PRI.... If you run it out of gas on PRI the reserve is gone too.

 

All good answers. Thanks guys. I can always count you this site.

 

ill ask another dumb question

can the gas be turned off????

i have yet to own a bike with an off position.

shure would make takin the tank off a lot less messy :cry:

 

The fuel should be off when the bike is not running and the petcock is set to either the "On" or "res" position. The petcock is a vacuum actuated unit. The second line coming off the petcock is the vacuum line. It goes to the #3 intake manifold. When the bike is running the intake is pulling vacuum. This pulls on the rubber diaphraghm inside the petcock which pulls a spring loaded plunger with an oring at it's end off of a seat, thus allowing fuel to flow. Turn the bike off and the vacuum stops, thus allowing the spring on the plunger to push the oring back into it's seat, thus stopping the fow of fuel. In the "pri" postion the plunger is pushed back unseating the plunger/oring and allowing fuel to flow without the need for vacuum.
If you disconnect your fuel line from the petcock in either the "on" or "res" position to remove your tank while the engine is off, the fuel should not flow. If it does then the petcock needs repairing. This could be as simple as replacing the oring or stretching the spring so it pushes the oring back in with enough pressure. It may also require replacing the rubber diaphraghm which could be torn. If it is torn it will allow fuel to flow in any position.

 

ty blue maxim good info

jeez i think im gonna like it here

 

Are you trying to challenge my position of "asks dumb questions guy"???

 

oh not at all......but i fit in well with these kinda threads :lol: :lol: :lol:

 

No such thing as a dumb question, only dumb answers. Ask away but do try the search function to see if the question has been answered already. Of course it is nice to have a rehash of an old topic, brings new ideas in.

 

...Another engine-dumb guy here. Thanks for a greater understanding of my puzzling petcock.

(**EDIT: See, my idea here is that if I find any post which helps me out, to add a comment or thank-you, so that if I need a refresher course, I don't have to use the forum's search engine - I'll only have to find my own posts.)

 

It's great for the post count too! err ahh..remind me to be more polite in the future. :idea:

 

(Good point - that IS the main downside of my idea: I get to look like a poser who cares about racking up a postcount. BTW, sweet looking bike: http://xjbikes.com/Forums/viewtopic/t=4239.html )

 

My 82 xj1100 has an "off" position as well as on, reserve and prime.

 

I changed mine to a manual for peace of mind and it was $15. Mostly because it was $15.

 

The XJ1100 has a completely SEPARATE Vacuum Operated Fuel Shut-off System that functions to regulate the Fuel Flow from the Petcocks.

There's also a good deal of PLUMBING that need to be checked for Kinks and proper routing.

The Fuel EXITS the Petcocks and Flows to the VACUUM Valve which Opens and Closes from Manifold Vacuum.

 

thats great info I had no clue and was running my 82 750 on pri till it ran off of gas and i thought something was really wrong with it. Thanks for the info..

 

Direct answers to your not-that-dumb questions:

1. The "arrow" is on the handle, so you point the handle at your "selection."

2. Not a bad idea.

3. Shouldn't. If this happens, it indicates a carburetor float valve problem or mis-adjustment. The floats should be able to shut off fuel even if the petcock is on PRI.