Gas in oil case AGAIN!

[Lambo]

I have had the carburetors cleaned 2 times and replaced the petcock 2 times and still getting gas in oil. What's a brother to do beside send it to the junk yard?
Any help that will lead to the solution and repair would be great.
Thanks.
Desperate

[7981GS]

Float needles/seats replaced?
Float levels set correctly?

Change the oil... again.

Daniel

[nofxbob]

If you set it on prime does fuel keep flowing when it's not running? If all else fails you can always send it to me.

[tom203]

If you set it on prime does fuel keep flowing when it's not running? If all else fails you can always send it to me.

But more importantly, when you set it on "ON" or "RES" (and bike is not running) does gas stop flowing? Disconnect feed hose to carbs and observe whether the petcock is working- let it sit overnight maybe.Did you buy new petcocks or previously worn out ones?

[bwringer]

The phrase "...had the carburetors cleaned..." implies that someone else did the work. There's your trouble, I'll bet. You don't know what was done or how well it was done.

Also, you have failed to reveal what sort of conveyance we're discussing. Please put your bike's model and year in your sig. Makes a difference.


More to the point, overflows like this have only a few causes.

If the overflow happens when the bike is sitting, you must first have a petcock that's leaking or has been improperly set to "prime". The "on" and "reserve" positions are where the petcock is vacuum operated, and it must be set to one of these positions when the bike is parked.

Secondly, if you have overflows when the bike is running, there are three possible causes:

1) Improper/worn needle valves; badly miscalibrated float height

2) Debris propping open the needle valves (common when an old petcock is forced to move, which dislodges bits of internal corrosion). Stock petcocks have very effective filters, so debris from the tank usually doesn't cause this problem.

3) Bad o-rings or seals on the needle valve seats. Most common when the o-rings in CV carbs aren't replaced or are installed improperly.


One thing to remember is that the needle valves in the carbs are NOT designed to hold back a tankful of fuel. If you leave the petcock on prime or install a manual petcock and leave it on, you WILL get gas in the oil over the course of a day or two, even if everything in the carbs is working perfectly.

[jbs80106]

What bwinger said...

Only other suggestion would be to pull the fuel flow to the carbs when parked in the garage...feed it into a gas can...would solve the problem between rides but not the root cause...