Restrictive petcock

[mixongw]

FYI

After disassembling the petcock and finding out that the spring that controls the reserve function was trashed, I modified it temporaily and ran the fuel line straight to the carbs. The old gal never ran so good! I guess the flow was being restricted.

 

[IanFrancisco]

I'm not a big fan of these vacuum petcocks. A luxury item that can be a pita and strand you somewhere if the diaphragm leaks. I was tempted to install a manual petcock while searching for the correct diaphragm and using super-glue to patch the old leaky one every week. If I wasn't such a cheapo I'd have gone with a Pingel but didn't like the adapter plate needed. One more place to spring a leak...

 

[kahuna]

petcock

petcock

miagi says pingel and gas flow good but always remember gas on gas off

 

[jeff.saunders]

One of the insidious problems with the vacuum petcocks - if the diaphragm starts to leak, fuel can flow down the vacuum hose into the carbs and directly into the cylinder if the bike is sitting at the wrong angle.

I had a customer whose bike developed a knock at the bottom end - in talking with him he mentioned a strange problem he'd seen for a few weeks before the engine went bad - his oil level was going up... he'd trashed his engine by running very diluted oil for some period of time. He had no fuel on the floor of his garage to warn him of the problem.

 

[IanFrancisco]

There's a "tears in my beer" story for ya - i didn't know gas in the oil was that terminal a problem, thought it would evaporate or something, but come to think of it it takes a long time to evaporate when it's spilt on the ground...

 

[Jethro]

I like my Pingel. Turning it off becomes second nature.

 

[ccratin]

The gas doesn't evaporate inside the crankcase because there's no good way for it to escape. I've had the good ol fuel in the oil problem too. Fortunately noticed that the tank was way lower than I remembered from three weeks before! The crankcase overfilled the container I was draining into! There was at least a gallon of gas in it . . . .

 

[jeff.saunders]

When we drained this bike of it's 'oil', it just gushed out of the bike and overflowed the oil pan we use - so there had to be well in excess of 6+ quarts of oil/fuel in the bike.

 

[prism4]

Fuel In Oil

Fuel In Oil

Have a 1980 GS1100l - I just changed the oil and found a lot of fuel in the crankcase. ? I was told that the petcock may not be working correctly. I took the plugs out and found the number 2 plug to be wet. Could it be that the perrtcock is leaking fuel into the vaccum? PLease help. I do not have a lot of bike experience. Thanks

 

[gremlin]

prism4



to test if you petcock is not working right just unplug it. put a can under it to catch gas. you can use a soup can or coke can with a wire to hold it up. if you get a lot of drips then its your petcock.


since you do not have a lot of bike experience. try to find some one in your area that will teach you how to clean the carbs. if your lucky there may be some one close.

if there is nobody close a cheep dig camra and this fourm we can get almost any thing done

 

[prism4]

Testing petcock

Testing petcock

Well I took it off and the only thing that i saw was a few drips out of the vaccum line buit not much at all. Would it drip more if the engine as on??
Thanks

 

[ccratin]

If there were drips coming from the vacuum line, that is a sure sign your petcock's diaphragm is leaking. You have to rebuild it. The vacuum line should be dry.

Get your rebuild kit from cycle re-cycle. search here for links to them.

 

[prism4]

Thanks I have to postings and your advice seems to match everyone elses. i am off to the store to see if I can get a rebuit kit at the local Suzuki shop. If not i will order it online.

 

[IanFrancisco]

Thanks I have to postings and your advice seems to match everyone elses. i am off to the store to see if I can get a rebuit kit at the local Suzuki shop. If not i will order it online.

I think all the dealer will do is order a whole new petcock. Rebuild kits are avialable on eBay (seller name= siriusconinc ) or from www.oldbikebarn.com

Some people have complained about Old Bike Barn but they had the odd sized (larger, ~42mm square) petcock diaphragm I needed and I didn't have any problem buying from them.

 

[prism4]

Bad petcock???

Bad petcock???

Well I am not so sure if my petcock is rebuilable. I took it off and did some vaccum test and no matter which position I had it in, prime or on. the vaccum seem to remain the same. No change whatsoever?? I dont want to spend $30 on a rebuilt kit if the petcock is bad. Can someone give me a good detail explanation on what to look for?

You can see my actual petcock here http://www.telforceusa.com/petcock

 

[ccratin]

I can't imagine why it would not be rebuildable. I assume your test showed it was not holding vacuum? The rebuilt kit contains a new diaphragm and o-rings and should restore it to like new.

Chris

 

[prism4]

what should i use to clean it with for the rebuild?

 

[Hoomgar]

I'm an advocate of the stock vacuum petcocks. I know for myself that a pingle would spell certain death for my bike if left in my control. The stock petcocks however work flawlessly if properly maintained. Any bike that gets close to or over two decades old should have all fuel delivery components rebuilt anyway so blaming the design is a mute point since it most likely worked fine for the last 15 years and finally needing a rebuild is therefore not a crime. Rebuild kits can be had anywhere almost like local dealers or eBay sellers. I use Georgefix on eBay a lot. Just email him. A rebuild kit can be had for a fraction of the cost of a pingle and a 1/10 of the installation time compared to converting to a pingle.

Just my two cents but I encourage rebuilding and keeping the stock petcock.

Once all the rubber bits are removed simply clean it out good with carb cleaner and a soft brissel brush if needed. I have used vacuum petcocks on all my bikes over the last 23 years and have only had to rebuild 2 in that time. Both on separate bikes. Easy, normal maintenence.

Hope that helps.

 

[ccratin]

Check that diaphragm closely. Is the rubber cracking/brittle looking? Is it separated from the little piston? If there is nothing broken on the casting, there's no reason it won't rebuild.

 

[prism4]

Okay I went and got a rebuild kit put it all together and still have the drips?? I applied vaccum to the line and it does not hold. slowly escapes. What should it hold at?