Anyone know of a high quality vacuum petcock?

[blittlej]

Put the OEM petcock in. Problem solved. Just finishing out the thread. If you need a new petcock buy a OEM rebuild kit. The $16 petcocks on ebay ones are junk. My bike still leaks when I have it on PRI when it is parked in the garage. But, I think that might be the float needles. That is my next project.

[jsandidge]

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.

[bobgroger]

Put the OEM petcock in. Problem solved. Just finishing out the thread. If you need a new petcock buy a OEM rebuild kit. The $16 petcocks on ebay ones are junk. My bike still leaks when I have it on PRI when it is parked in the garage. But, I think that might be the float needles. That is my next project.

It is most likely the o-rings around the needle seats. They keep gas from bypassing the needle and seat. Get an o-ring kit from cycleorings.com.

[gsgeezer]

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.

The OEM ones work fine, as long as you follow the above advise.
I rebuilt the OEM a couple times then got a different petcock (non-vacuum).

[blittlej]

Aaaah good to know. So, there is nothing wrong with the needles. The PRI position was not designed to do that.

[blittlej]

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

[blittlej]

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.

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.

[gsgeezer]

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!!)

[blittlej]

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

[blittlej]

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!!