1980 GS1000 GT Petcock question

[norman1950]

Getting closer to having the bike up and running. Put fuel in the tank and it just leaks around the petcock like crazy. So I open it up and look under the diaphragm and notice some gunk build up and cleaned that up. Now my question is; is there supposed to be a spring under the diaphragm to keep it "closed" until the vacuum sucks it open?

Hope this is making sense.

I have attached a picture of where I thought a spring might go, but can't find any pictures showing an exploded view of the petcock.

Thank you for all your help.

[Dogma]

Yes, it should require vacuum to open it except on prime. Maybe prime too, I can't remember. I know the leverless '80 petcock requires vacuum to start flow on prime.

[tom203]

You got the leverless 1980 petcock ?- don't mess with it, get new one and eliminate it as problem. There will be plenty of other stuff to mess with! this guy will sell you one for $50

http://www.georgefixs.com/servlet/the-524/1980-GS550%2C-GS750%2C-GS850%2C/Detail

[yoshisakan]

I have two of the above mentioned leverless petcocks, and they both leak fuel when not under vacuum. I believe it's just the design. It doesn't cause a problem unless you unhook the carbs, you have to plug the line so fuel doesn't spill everywhere.

[850 Combat]

The 1000G does not have a leverless petcock. The E does, but not the G.

[norman1950]

I was going off Partzilla and from what was on the bike. It is showing the leverless for the GS1000GL (model T), not sure if that makes a difference or not.

Thinking new might be the way to go. Thanks for the info!

[Dogma]

If you have the G and not the GL, you should have the lever. That's the good one. I still replaced mine rather than rebuild, though.

[TowPilot]

1000G Petcock

Yes should be a spring.

Here is the strange situation with my 1980 1000G petcock. The original diaphragm was thick. It had like a quarter inch plate built in within the diaphragm. The new diaphragm was paper thin. Two of the bolts would bottom out with the new diaphragm. So I shortened the two bolts that were bottoming out to get a tight fit with the thin diaphragm. Using the original bolts with the new diaphragm would leak as not enough pressure to seal.

[Steve]

Yes, it should require vacuum to open it except on prime. Maybe prime too, I can't remember. I know the leverless '80 petcock requires vacuum to start flow on prime.

Only the leverless ones requires a bit of vacuum to start the flow on PRIme.

You got the leverless 1980 petcock ?- don't mess with it, get new one and eliminate it as problem.

The title of the thread says "1980 GS1000GT", but your signature says "GS1000L", so which is it?

I was going off Partzilla and from what was on the bike. It is showing the leverless for the GS1000GL (model T), not sure if that makes a difference or not.

Yes, it makes a BIG difference. My condolences on having the leverless petcock, get a new one. Even with the levered version, the success rate for rebuild kits seems to be about 10-15%, so just spend your money once, get a new one.

.

[850 Combat]

I've had the valve stick in my '80 leverless petcock. I bought a new one, but I'm pretty certain that the old one just needs a cleaning. Which I will eventually do.

[Dogma]

I've had the valve stick in my '80 leverless petcock. I bought a new one, but I'm pretty certain that the old one just needs a cleaning. Which I will eventually do.

If the leverless petcock is original and won't stay open, cleaning won't help. The plastic part of the valve shrinks, turning into a permanent vacuum leak. If it won't close, cleaning may help or reveal a faulty rubber bit.

[oldgrumpy]

You got the leverless 1980 petcock ?- don't mess with it, get new one and eliminate it as problem. There will be plenty of other stuff to mess with! this guy will sell you one for $50

http://www.georgefixs.com/servlet/th...S850%2C/Detail

hi guys this guy sell great petcocks i purchased 1 a few years ago no problems at all regards oldgrumpy

[norman1950]

Thank you for all your input. Have a new petcock coming in the mail.

[knewel]

i believe you have to keep the thicker gasket from your old diaphram. It goes between the two paper thin gaskets on the new one (just carefully stuff it through the hole. hold off on shortening the screws!