Petcock Replacement?

[Guest]

I have a 1979 GS850-G. I have rebuilt the carbs and they work great. My bike runs great, but pukes gas on the garage floor. I have rebuilt the petcock - replaced with a new petcock... Etc... Question: IS THERE A REPLACEMENT PETCOCK THAT I CAN MANUALLY TURN ON/OFF THE GAS THAT WILL FIT RIGHT IN THE EXISTING HOLES? TIA

[Denny Lee]

Petcock Replacement?

Is it normal for a completely functioning petcock to have a stream of gas coming out of the fuel opening when the petcock is set at ON - not prime - On. If this is a vacuum petcock - and it is - that should not be happening, correct? Only when the engine is running should there be enough back pressure to open up the vacuum seal and allow gas to flow through. Correct?

[kdo58]

http://www.thegsresources.com/_forum/showthread.php?t=167714&highlight=petcock+mod

[sprot850g]

Hi Denny,
my 850g also exhibits the same symptoms only in England it leaks petrol not gas! Have you also either replaced or fitted new seals to your petcock? Petrol still flows out even when the engine is not running,tap is in the "On" position. When left standing in my garage the next morning there's a small puddle of petrol on the floor, does this mean seals in the carbs are not functioning correctly? My bike is low milage (10,000) but had been stood for 20 years prior to my purchase,will this have any bearing?

[wayne4096]

I have the same problem with my 82 GS850G. The carbs run great but there is a pesky puddle of gas beneath my bike "sometimes". Which is to say that it may go weeks without leaking and then out of nowhere it does once more.

Here is my intended approach: Buy and install a simple ON/OFF fuel petcock downline of the factory petcock and then leave the factory petcock in the PRIME (or ON) position. Either way this should keep gas from reaching the carbs and ultimately filling the air filter compartment before weeping down the vent hose. Does anyone see a problem with this approach?

[gsgeezer]

I've rebuilt or replaced stock petcocks on old bikes a fair number of times.
I put a pingel on the gs, so no more of that, I hope!

[wayne4096]

Yes. You were right Old Skool. It would have been a band-aid. I found a petcock rebuild kit. That went well. While I had the tank pulled and drained I washed it out and found a tone of debris inside. I think some debris made it into the carbs and was responsible for the float needle not sealing. Thanks for the push in the right direction.

[sedelen]

Where is the gas ultimately leaking from...the carbs, then rebuild wasn't done right, bad o-rings combined with the float needles need polished as they tend to get grooves in them over the years and allow leakage instead of seating. Sometimes they need replaced, but more times than not, I've polished them with great success. Doubt the new petcock is the fault unless you didn't replace the the little washer/gaskets needed on the mounting bolts. And don't take offense to the carb rebuild comment, if your not familiar with these carbs, they can get you. http://www.mtsac.edu/~cliff/storage/...d_Tutorial.pdf

Surely you've read this, The caution on page 16 about leaving the petcock in "Prime"

http://www.mtsac.edu/~cliff/storage/gs/GS1100GL_OwnersManual.pdf

[sedelen]

If directed to me, I'm familiar with the article, but I've almost never used prime, except maybe once in the beginning of riding season if I've gone a long time without starting the bike, but usually, even if I don't ride all year, I always start the bike a couple times every week. And most of my bikes I end up keeping for any length of time, don't have prime as I replace all my petcocks with the on/off/res style, can't stand the vacuum petcocks.

edit;

That warning also doesn't mention you need to have an additional failure, prime setting alone SHOULD not overflow the carbs, and I've heard arguments about the amount of fuel in the tank overcoming the float needles, balderdash, not if functioning properly, my 5.8 gal tank doesn't overflow when accidentally left on with a full fuel tank(no vacuum style) because my float needles seal properly, but all it takes is some debris holding it open or a groove developing in the needle. I polish my needles annually when I recheck my float heights, at the beginning of every riding season(my own pet peeve) and I also run an inline fuel filter, which also DOES NOT restrict flow...more balderdash, unless your tank is spewing crap regularly.

Bottom line, petcock needs to be functioning as it should and the carbs need to be cleaned and adjusted properly.

Was directed at you and perhaps some members who don't know.
I'd say you got that all worked out down to the gnat's a*s.

[wayne4096]

Does anyone (OldSkool?) know of a petcock that fits the GS850G tank that doesn't use the vacuum line (on/off/res style)? Just this weekend I swapped the petcock on my LS650 for a suitable (non-vacuum) model from a Raptor. I'd like to do this on the GS850G rather than rely on a rebuilt vacuum model.