Leaking Gas from Carb Vent Hose?

[Guest]

I have owned a 1982 GS850L since new as original owner with 12,000 original miles. Took it off the road 8 years ago, and getting it ready to ride again. Before putting it away, changed oil, fogged cylinders and filled gas tank to the top. After 7 yrs in storage, drained gas tank, and carbs (opened screws under all 4 carbs until stopped draining). As of today, inside of tank is shiny silver; filled it up, changed oil & filter, bike turns over and starts easy! Only problem is gas spewing out black rubber hose behind air cleaner box. There are two of these blavk tubes side-by-side, clamped together. Seems like a downdraft or vent tube attached in-between two left side carbs. Happens when fuel swich is on, prime or reserve, and only when running. Wife says float is stuck and may have to rebuild carbs...I have no clue. Can anyone help, so I can finish everything else, and get back on the road?

Thanks-
"Rocketman" from Long Island, New York
Larry.Barasch@cbmoves.com

[GSstiny]

If you didnt have fuel stabilizer in it, theres a good chance the floats are gunked up and sticking. Other possibilites are crap coming in from the tank (doubtful, if the tank looks good inside), Needle valves that arent sealing properly because of wear, Bad needle valve seat gaskets/o-rings, or possibly a bad petcock diaphragm thats allowing fuel to flow down the vaccum lines and into the float bowls. That should at least give you something to look for.

This is something you want to fix, pronto. Ive heard several horror stories about people losing their bikes to fire because a carb dumped gas on a hot pipe. Ive seen it happen on mine. Its a little unnerving to say the least. :shock:

[Agtbar]

As stated a float or its needle valve is sticking down or worn/not sealing properly,thus not allowing the level to be set to its spec.The overfilling carb floatbowl is then spewing the excess out of the vent/overflow tube.
You will need to have the carbs disassembled and cleaned throughly, if they are separated you will have to resync them, not a bad idea anytime you work on them anyhow. And yes fule related fires are not kind to motorcycles so fix it quickly.

[Rocketman]

Thanks for the advice. Afte reading hundreds of links re: overflowing fuel, it seems like a common problem. This morning I'm going to try to remove float bowl from carb #1 (which is the only one I can reach the screws from), without removing the carbs at all. With any luck, I'll have a 50/50 chance of hitting the right one, and hopefully I can un-stick the float. If that doesn't work, off she comes, and time to get dirty.

[DaveDanger]

It's really not very difficult to remove the entire carb-set from these engines while they're still attached to the mounting rails that keep them together. Remove the fuel tank to give yourself some working room, then the airbox assembly, and disconnect the throttle and choke cables (easily done at the carb end) and unclamp the intake hoses. The whole carbset will slide out the side of the frame. At that point, flip them upside down on your workbench, kitchen table, ottoman or lap, and remove those pesky float bowls and do a good clean-out of that portion of the carb. Depending on what you find in there, you may want to order a set of o-rings from Mr Barr, and continue with a complete disassembly and cleaning. You'll be glad you did it down the road. There's an excellent series of instructions for disassembly and cleaning here on the site.

[Rocketman]

Thanks again for your quick responses. I took a chance yesterday and removed bowl from carb #1 (as #2 is not accessible). Fiddled around with float, and re-installed bowl. No more leaks from vent hose! Only thing is, bike will only turn over on full choke, with 1/2 throttle and runs for about 5 seconds @ 4000 rpm and shuts off. My guess is after 8 yrs of sleeping, carbs need cleaning and rebuilding. Gonna bring it to a guy to do a complete overhaul, including carbs, front forks, brake fluid and hoses, and tune up. Hope I can get it running like new out of the crate in '82. Will advise on progress. Took my bike off the road in 1997, right before my first son was born. Now 3 kids later, time to feel the breeze again. Thanks to everyone for your input, and safe riding!
P.S. (Hope this is a politically correct thing to ask here...), any reason to NOT rejuvenate my '82 850GSL and find a Madura 1200 to work on. Loved the looks of that bike years ago, but never got one.