Gas leak

[metalistik]

Well, it's some kind of a phantom gas leak to be exact. It goes away and then comes back.
The leak seems to be coming from the air cleaner. I suppose that it's the carbs but I'm not sure. It only happens when the bike is sitting and, as I've more or less determined, has been ridden for a while. It comes out of the left side of the air cleaner, but I guess that's because the bike is leaning left when it's on the side stand. I seem to loose about a 1/4 gal of gas overnight if this occurs. Any thoughts?
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1979 XS1100 Special - Daily driver

[dbeardslee]

Sounds like the diaphram in the octy isn't doing it's job shutting off the gas. Also sounds like your fuel valves aren't sealing. Not only will the gas leak back into your airbox, it'll go the other way too - into the cylinder, past the rings, and into your oil. Gas thinned oil is a BAD thing - it has been known to damage crankshaft bearings. Dip a stick into your oil through the filler hole, and see if it lights easily with a match. If it does, you've got gas in your oil, and you need to change it. You can also put your nose down by the filler hole and see if you can smell gas there. In the short term you should be able to stop the leakage by turning your petcocks to the 'off' position when it sits - assuming they don't leak.

[metalistik]

Thanks for the info. I thought that it was one of the petcocks leaking since it was set on prime by accident, but it still leaks. Do I have to pull the carbs to change the seals?

[foreda]

Leaking carbs

You'll be better off pulling the carbs to replace needles and seats. It's also a good idea to set them up and test the floats/seats before reinstalling on the bike. You can rig up your tank with some fuel hose and do this pretty easily. I have and old lawn mower tank that I rigged up for testing float height and proper seating.

[dbeardslee]

You have to pull them to change the fuel valves. Personally I like the viton tipped XV920 valves - Viton to metal seals better than metal to metal. You don't have to pull the carbs to rebuild the octy. A lot of people opt to remove the octy and just use they're petcocks manually - just have to remember to turn them on and off. It's easy enough to tell if your petcocks are leaking - turn them to the 'off' position, disconnect the fuel line at the petcock and see if gas still comes out.

[metalistik]

Thanks for the help, guys. I've been shutting the petcocks off manually and that seems to have solved the problem for now. However, I have to keep reminding myself to turn them back on... Already took off and then stalled out twice... Duh..

[MindWebs]

it's all good...

yep... been there done that..

i just rebuilt my petcocks and octy 2 weeks ago..

easy to do and 1 - $30 kit takes care of all 3 parts.

ebay, georgefix is the seller i prefer

he also has the carb rebuild kits for your/my bike

i think those were $74 shipped

all the parts you need to build them up good as new.

[redbone]

hey metal, i have a george fix petcock rebuild kit for a special that i purchased a couple months back and never used. still in the original package.
i'll sell for 28$ shipping included. i do have paypal acct.
if interested please send me a PM.
thans
redbone

[Crazcnuk]

Just try tapping on the float bowls with a wrench or small hammer first. You may get it to stop. It's easier if you know which carb has the problem.

[foreda]

Check oil often

Make sure you check you're oil regularly until you get that fixed.

[Bigfoot]

Prime will bypass the octy. If you have a leak, that means you have a stuck float as well.

Thanks for the info. I thought that it was one of the petcocks leaking since it was set on prime by accident, but it still leaks. Do I have to pull the carbs to change the seals?