Anyone know of a high quality vacuum petcock?

[Guest]

I do not have the O-ring model. I was looking specifically for those when I opened it up.

 

[Guest]

But, can you leave the non-vaccum petcock open for more than 30 seconds without fuel overflowing from the carb?

 

[cowboyup3371]

What do you mean by not having an O-ring model? All of the carbs I have seen from other members on this site have O-rings in specific areas of the carbs. In fact, reading the parts fiche there are orings in them

 

[Steve]

I <think> he was referring to the o-ring in the petcock that shuts off the fuel. :-k

Every GS petcock I have had apart has had an o-ring there. You have to have something somewhat flexible to seat against the inside of the body to positively shut of fuel flow. Unless you are the original owner of the bike and can guarantee that nobody has ever worked on it without your supervision, you have no idea who has done what, so quite literally, anything is possible.

.

 

[tom203]

But, can you leave the non-vaccum petcock open for more than 30 seconds without fuel overflowing from the carb?

Sure as long as your carbs have decent needle seats- they should restrict fuel intake for half hour*


* my wild unfounded guess

 

[hannibal]

No, there's no O ring on the float valve, just a thin fiber washer.

 

[Guest]

Sure as long as your carbs have decent needle seats- they should restrict fuel intake for half hour*

Yeah, I try to remember to turn mine off. (I have two bikes with them, so it is easier to remember to turn to off!!)

 

[Guest]

Now even with a perfect petcock. One of the carbs started overflowing while I was in traffic. MAN, this problem is hard to solve. So, it must be the float valves. But, I cleaned them. So, with float valves do I need to replace the brass seat too? Or just the float valve needle?

 

[tom203]

Now even with a perfect petcock. One of the carbs started overflowing while I was in traffic. MAN, this problem is hard to solve. So, it must be the float valves. But, I cleaned them. So, with float valves do I need to replace the brass seat too? Or just the float valve needle?

Did you replace the gaskets under the seats....part #13

https://www.partzilla.com/catalog/suzuki/motorcycle/1979/gs1000en/carburetor-gs1000n

 

[Guest]

Yep that was done. They were inexpensive. So, replaced them while I was in there. When I was in traffic I would give the engine gas and gas would come out of the overflow tubes. I drove it a block and did the same thing. Then it stopped. So, it comes and goes.


Thank you for you input!!

 

[tom203]

Hmmm...I'm thinking you should correct this before you make the 6 o'clock news. Which carb (or carbs) is overflowing so easily? Float heights good? Any chance of a float bowl gasket hanging up a float?

 

[BigD_83]

Hmmm...I'm thinking you should correct this before you make the 6 o'clock news. Which carb (or carbs) is overflowing so easily? Float heights good? Any chance of a float bowl gasket hanging up a float?

I was having similar thoughts...some of the aftermarket gaskets are cut a little large

 

[Guest]

mmmm interesting. Never thought of that. Gasket hanging up on the carb float. Another question, are the carb floats good forever? They are not brass or plastic. Some kind of compressed material.

 

[Guest]

So, the OEM suzuki petcock works like a champ. It does not leak even with a full tank of gas (the $16 ebay look alike did). I ordered and replaced the carb #1 float needle and seat. Now the bike does not leak gas even on PRI. Look at the old needle and seat. There was new microscopic black trash in the seat. That was probably the issue. The previous owner let the bike sit around for years. I cleaned out the carbs and other stuff. But, I guess junk is still breaking loose from places I can not see. Oh well, It is what I signed up for and I am learning.

 

[bwringer]

If you really want the problem solved, don't leave your bike parked with the petcock on PRI. PRI (prime) should only be used to fill the bowls after the carbs have been serviced or the bike has been sitting long enough for evaporation to occur. You should only leave the petcock set to PRI for about 30 seconds or so, then turn it to ON or RES. The float needles were never designed to hold fuel back while the bike isn't running.

Emphasis added. Leave it on prime and yes, even a perfectly functioning system WILL leak.


Sounds like you did have a damaged or low-rent needle and seat as well.

Thanks for reporting back with a happy ending!


Several times, I've seen leaks caused by forcing an old petcock to move after it's been in the "ON" position for years. Even if the valve still functions, little corrosion crudniks from inside the petcock can make their way into the needles and seats and prop the needles open.

 

[Guest]

"I've seen leaks caused by forcing an old petcock to move after it's been in the "ON" position for years. Even if the valve still functions, little corrosion crudniks from inside the petcock can make their way into the needles and seats and prop the needles open."

I bet that is what happened. Thanks for the resolution. Now back to enjoying worry free rides on the bike.