Just about had it with my Petcock

[GateKeeper]

try a performance auto shop as well, they might have something.....

.

[sedelen]

Wish I was there to help you sort it out.
Petcocks can be trying. You have to have a clear head when working on them, and still they can give you fits.

I'm not sure which petcock you're using that physically fits your tank.
I believe you're using one similar to this one.


I once saw a thread where a guy filed away the physical stop that kept the lever from pointing upright, believe he had to shorten the lever a bit also so it would clear his tank. But he said in that position, the lever pointing up, it wouldn't allow fuel to flow. Now I haven't tried this myself,
and I'm hoping you could find a way other than this, but you seem to be at the desperation point. If all else fails you could try this, no gaurantee's.

[tom203]

I'd love to find a set up where i have an 'off' setting. that way, if the carbs flood out, it's my own fault. thanks, everyone, for the feedback. I'm going to investigate the bolt spacing and see what i might adapt for this problem

Yeah, measure. Most popular petcock has 44 mm bolt centerline spacing with both fuel outlet and vac fitting facing toward rear.The vacuum petcock works well- but not forever. My first lasted 31 years.

[caferacer81]

I have the same overflow/ leak problem with my '81 450 and thought that service kit (20$) could solve the problem. Unfortunately previous owner had taken all the stuff out from petcock and sealed the vacuum line. The service kit had no spring on it and neither Suzuki nor other mc dealers doesn't offer a replacement. So I asked advice from our Finnish veteran motorcycle forum, if they knew where to look for the spring. The solutions given to me were a) buy a new petcock (70$ inc. mail) b) get rid off all the stuff inside the petcock (previous owners solution-> not working) or c) get inline valve. Probably needless to say that back and pride won't bend to buy a new one just because of a one spring. And if it would come to buying a new petcock, I probably would get a manual one with adapter.

But it would be nice to hear afterwards what was your final solution.

[MOC]

I'm probably going to go for the brass shut off valve in line with the existing fuel lines. the inside diameter of the fuel outlet on the factory petcock is 1/4 inch, so anything within that spec should flow enough fuel for my carbs to drink from comfortably. I don't plan on owning this bike forever, so i'd like to keep my investments in it somewhat modest.

not sure when i'll get around to it, however. had a break in last night, and i've been spending my time/money sorting out our security issues here at the house.

thanks as usual for the feedback fellas.

[sedelen]

had a break in last night, and i've been spending my time/money sorting out our security issues here at the house.

thanks as usual for the feedback fellas.

If it weren't for bad luck you wouldn't have any luck at all.
Maybe they were after your petcock
Hopefully things will start turning around for you.

[Gateway]

Bite the the bullet go to Suzuki and buy a new one and be done w it.

[MOC]

I'm worried that the design of my petcock lends itself to this kind of failure. if i replace all the moving parts, and the damn thing STILL leaks, i am concerned that an identical replacement would end up doing the same thing.

with that said, the petcock on my bike right now is basically this one:

http://www.ebay.com/itm/New-Fuel-Petcock-Valve-1977-1981-GS750-E-GS850-G-GS1000-G-Genuine-Suzuki-K84-/271194927323?pt=Motorcycles_Parts_Accessories&fits=Model%3AGS&hash=item3f247a30db&vxp=mtr

I wouldn't buy it at that price, but am I barking up the correct tree here? Factory stock replacement? like i said, i'd like to keep my investments modest if possible, but if this improves the value of the bike in the long run i may bite the proverbial bullet.

[rustybronco]

You may find your answer in this thread.

http://thegsresources.com/_forum/showpost.php?p=1799962&postcount=1

After taking it apart, I found the piston on the diaphragm was about 1/2mm too short- another member pointed this out in my other thread.

[sedelen]

I'm worried that the design of my petcock lends itself to this kind of failure. if i replace all the moving parts, and the damn thing STILL leaks, i am concerned that an identical replacement would end up doing the same thing.

with that said, the petcock on my bike right now is basically this one:

http://www.ebay.com/itm/New-Fuel-Petcock-Valve-1977-1981-GS750-E-GS850-G-GS1000-G-Genuine-Suzuki-K84-/271194927323?pt=Motorcycles_Parts_Accessories&fits=Model%3AGS&hash=item3f247a30db&vxp=mtr

I wouldn't buy it at that price, but am I barking up the correct tree here? Factory stock replacement? like i said, i'd like to keep my investments modest if possible, but if this improves the value of the bike in the long run i may bite the proverbial bullet.

I know it's expensive at $99. It could be worse. A '78, '79 GS1000 petcock new will cost you $267 and change plus shipping!
Item 1-1 on this fiche.

http://www.boulevardsuzuki.com/fiche_section_detail.asp?section=95436&category=Motorcycles&make=SUZUKI&year=1978&fveh=2146

Therefore I had to rebuild several of mine. I got all working save one which I used for parts. Problem is there's several things that can make them leak, like that itty bitty O-ring on the diaphram, that what you get in the kits are too small. Also there's a 4 holed selector ring that gets squished and hard and doesn't seal properly under the selector lever.


Plus, there's a breather hole that gets plugged up on the outside of the petcock and gets clogged and won't let your petcock breathe, keeps the fuel flowing so to speak. This hole aligns with the holes in the diaphram and the block the diaphram sits in between.

Of course there's always that possibility you could use as a last resort that I put in one of my other posts to you. I can't gaurantee it'll work, but others have done it. You file off that physical stop that keeps the selector from pointing straight up, and you might have to shorten your selector handle so it will clear the tank. But it's supposed to stop fuel from flowing with the selector switch pointing straight up.

[MOC]

the more i think about it, the more i think you guys are right about that rebuild kit and the piston in it. i'm going to have a look at it when i get home. i'm also liking the idea that the breather hole on the back of the diaphragm is plugged for some reason. one of my symptoms is that the petcock is slow to return to Off after the bike is shut off (hence the need for blowing into the vac line).

the 4 holed gasket and seal around the selector valve worked great for fixing the leak out of the face of the petcock. it also helped to tighten that ring shaped leaf spring a smidge. now its just a slow drip out of the fuel port. I'm going to tear into it again and see if i can isolate the issue.

Also: I just picked up a new laptop so i should be able to cobble together some pictures/video of the issue if i can find time tonight or tomorrow.

thanks for the help fellas

[sedelen]

Don't pull your hair out, I mean really.
You want a cheap fix, here's cheap!
Read post number 1 in this thread.

http://www.thegsresources.com/_forum/showthread.php?t=167714&highlight=Petcock+Leak&page=3

[sedelen]

the more i think about it, the more i think you guys are right about that rebuild kit and the piston in it. i'm going to have a look at it when i get home. i'm also liking the idea that the breather hole on the back of the diaphragm is plugged for some reason. one of my symptoms is that the petcock is slow to return to Off after the bike is shut off (hence the need for blowing into the vac line).

the 4 holed gasket and seal around the selector valve worked great for fixing the leak out of the face of the petcock. it also helped to tighten that ring shaped leaf spring a smidge. now its just a slow drip out of the fuel port. I'm going to tear into it again and see if i can isolate the issue.

Also: I just picked up a new laptop so i should be able to cobble together some pictures/video of the issue if i can find time tonight or tomorrow.

thanks for the help fellas

The breather hole I'm talking about is on the front of the outside of the petcock and goes through the petcock housing and should align with the hole in the diaphram and the hole in the diaphram block. Here's a pic of the "hole" from my petcock taken moments ago.
It looks like just a tiny speck, but it is clearly visible, here's a clue, the shadow goes right accross the top of it. Can't see it yet, it's above the fuel nipple, on the front part of that square block the diaphram sits up against.


Anyways, before you do anything else, be sure to read this!

http://members.dslextreme.com/users/storagecliff1/images/suzuki_petcock_rebuild.pdf

[MOC]

yeah, i know exactly what you're talking about. there are holes in the replacement diaphragms that are supposed to line up with it. i need to make sure everything is clear.

[sedelen]

This was my petcock testing station using a spare tank I had lying around.
Basically all you need to do is to have a "catch" tank to catch the fuel from when it flows. Fill your tank up enough to where it would normally flow in the "ON" position. Turn it to "Prime" and begin the flow, then to "On" and it should stop. Pour what flowed while it was in Prime back into the tank and put the hose back in and see if it stops flowing completely while left in the "On" position. If you don't have enough fuel for it to flow in "ON" you may get a false reading, therefore you can check it in "Reserve" also. Allot of people get the Prime and Reserve position mixed up, The petcock here is in the "Reserve" position.