alright now i am having a bad day - need petcock advice

[allisonmo2]

i always leave my petcocks on and tonight when i got home from getting dinner i look over at my bike and see a big big puddle! i had gas pouring off i believe the bottom of the airbox. what would cause fuel to run out all of a sudden? could it pour out of the back of the carbs into the airbox?

[don07tncav]

Yes it can and also check your oil. Gas can also get into the oil. The Tech Tips section has a lot of gereat info about this problem.

[allisonmo2]

i did a search and came up with 2 things.
one i need to check and mabye change the oil before i ride anywhere. i'll do that 1st tomorrow.

2nd i know nothing past the basic principle of how a carb works. i read that my floats may be sticking open? and that is why the fuel is leaking so i will pull the airbox and see if that is the case.


are there any websites that go into carb work with actual pictures? i read the tech tips and while the info seems good, i am a little hesitant to dive into the carbs without the proper experience.

[don07tncav]

I was the same way about messing with the carbs. I printed out some of the best threads and did it. After a while it goes faster and easier!!

[John]

The 80-81 carbs have the float seats that are pushed in and sealed with an O ring. That O ring can leak and that can also cause the problem. The float needles may be sealing but the O ring can still leak. Don't run the engine until you determine the cause, get it repaired and change the oil. Also, turn the petcocks off when your not riding. Pull the bottom of the airbox off and turn the fuel on. Look up into the carb boots and you should be able to see which carb is leaking.

[Winterhawk]

A good OEM needle seat sometimes can't hold back the fuel. You've got a bad petcock, some where. Pull off the fuel line and check them.

[xj11john]

dont leave petcocks on

Leaving your petcocks on is asking for trouble, I used to do it and I learned after haveing to change oil several times.

After that I read threads on this awsome website, and went through the carbs found that my needles had a ring around them, and that the push in seat had bad o-rings, also one seat had a rough-not a smooth surface for the needle to "seat" into.

After polishing the seats with chrome polish (a tip I learned here),
and replaceing the needles and o-rings, resetting the float levels to the right hieght (also tech tips on how to do that), and alittle trial and error, - no more gassy oil, and a good running bike.

A little effort and this web site and tips, and you will be a pro on your carbs, good luck.

[prometheus578]

You have two probs here. These bikes have vacuum petcocks, meaning that they should only flow when the bike is running. If your carbs are overflowing, then the petcocks need to be rebuilt, as they're not shutting off the fuel.
Second prob are the float needles. (Or the seat's O'ring. as John opines) They are the second line of defense again' overflowing carbs.
Any dealer should be able to match up your float needles (I think we sell them for $4.95)
After replacing the needles, (or doing ANY kind of carb work), always hook them up to a fuel source and "bench test" them for leaks before reinstalling them. Nothing worse than having to pull carbs off a bike after you've just put them back on 'cause they still leak.
Checking a vacumm petcock is easy. Set it to run or res. and pull the fuel line. If fuel flows or drips out, I would think that's a good indication that something's not right.

[xj11john]

Petcocks leaking

Oh one other thing was that I had a leaking petcock and I read the tips here or it may have been a thread, do a search and you'll find a tip on bending the washer that is right under the valve.

bending the washer alittle more so it has more tension and contact with the valve, helps it seal better. Also you may have a tear in the rubber gasket, one of the holes on mine had a slight gouge or nick out of it, so I moved that hole to the position that just had a peg-(per the tip I read), and presto no more leaking petcock.

[84xj1100]

allisonmo2,

You may want to check out the thread titled "petcocks on or off after a ride" for some further advise/hits/tips on petcock positions and the logic behind the selections.