Petcock leak

[lindsaylohan]

Hello all,

It took me months to stumble into this site and I have been trolling it for days now. I've read probably over a hundred threads in entirety (including the starter threads). This is a wealth of info that would probably be lost if not for the internet.

This may be a stupid question, but I couldn't find the answer anywhere. And once I have the answer the bike will be put together and I will post pics...

I just bought a '78 GS750. After some time in the shop (I don't have a garage) I got the bike back with a leaky gas tank. That is fixed. Now after I reattach the petcock I have a leak. I started by buying a new petcock. Same problem.

The leak appears to be coming from where the petcock bolts thread into the tank or around the seam where the petcock meets the tank. I don't think I lost any washers or anything after I originally took it off (I was meticulous about separating parts in ziplocks).

I am basically just trusting the oval gasket on the top of the petcock to seal it up.

Should I be doing something else? Such as using something in the threads before screwing the bolts in (like loctite)? Am I skipping some kind of prepping other than cleaning the surface of the tank? Should there be any washers or rubber grommets around the bolts?

I've googled and googled and I bought a Clymer...I have no idea. I don't see any kind of warping, it butts together with no noticable gaps.

Thanks in advance...

PS. I'm going to rebuild the other one just to have around. How do I get the hard plastic square piece back between the two soft square pieces on the metal nub (vacuum side, sorry it is hard to describe).

[psyguy]

welcome

the diagram shows gaskets on the screws

[psyguy]

i see you figured the right of passage on this site

And once I have the answer the bike will be put together and I will post pics...

.................................................. .

[80GS750]

i think #6 in those pics are just lock washers......

or regular flat washers....



i would say get yourself some hylomar gasket maker, its the best stuff for these surfaces, then reassemble it. i put it on the tank, and the petcock, and i have no issues...

[SqDancerLynn1]

In the parts diagrams it is called a gasket

[Nessism]

#6 is a washer with a rubber seal vulcanized on the inside so it will seal (sometimes called a Dowty seal). A must have item.

[lindsaylohan]

Thanks for the input. I think I'm going to try to find these dowty washers today and some gasoline resistant teflon type tape for the threads.

On this pic you can see the square piece. Somehow I have to get a hard piece of plastic back between the two layers of soft gasket square layers. Anyone ever pull this off? I imagine I am going to tear the thin layers up.

http://www.siriusconinc.com/ebayimages/18-4354.jpg

[psyguy]

On this pic you can see the square piece. Somehow I have to get a hard piece of plastic back between the two layers of soft gasket square layers. Anyone ever pull this off? I imagine I am going to tear the thin layers up.
http://www.siriusconinc.com/ebayimages/18-4354.jpg

most people advise against the fuel tap rebuild kits (not sure why though)

[onchiman]

Copper washers will also work and should be available at most hardware stores.

[Craiger]

I have nothing to add other than a welcome to the forum. It's good to see you're out of rehab.

[ryonker]

So the new petcock you bought is the oem or stock petcock?

I replaced my older petcock with an aftermarket one from Z1 and it works great. You just have to be sure and turn it off if you park for a while.

However, after installing my new petcock, I started getting a leak somewhere to. I was getting really p-oed because I couldn't tell where it was leaking. It actually looked like it was leaking right out of the inerd of the petcock.

I was ready to get a new one, when I decided to place around with my fuel line. There must of been a tine opening/air leaking at the pet cock end of the fuel line. Fuel was actually being pushed back up and around the petcock making it a look like a mystery leak from the petcock itself. Once the fuel line was properly secured, NO LEAK.

Just some thoughts.

Good luck LL!

Rick

[Dogma]

Thanks for the input. I think I'm going to try to find these dowty washers today and some gasoline resistant teflon type tape for the threads.

On this pic you can see the square piece. Somehow I have to get a hard piece of plastic back between the two layers of soft gasket square layers. Anyone ever pull this off? I imagine I am going to tear the thin layers up.


http://www.siriusconinc.com/ebayimages/18-4354.jpg

Don't worry about taping the threads. The washer will do all the necessary sealing. I've already been down this road.

I'm not clear on the square thing you're talking about though. Not sure what you're asking about.

[82Shafty]

Hear Hear to Dowty Washers!

I tried to respond last night but it kept saying server is too busy try again later.

A GSresource internet traffic jam.

[82Shafty]

Don't worry about taping the threads. The washer will do all the necessary sealing. I've already been down this road.

I'm not clear on the square thing you're talking about though. Not sure what you're asking about.

Shouldn't you be out fixing a master cyl right about now?

[Dogma]

Shouldn't you be out fixing a master cyl right about now?

That's scheduled for the morning of the 4th. Can't get to it before that. the wife has the Grand Prix, I have the GS. No hurry.