Petcock part: What is this SUPPOSED to look like...

[Guest]

...and what is it called? I'm working on an 82 GS750E and am trying to fix the petcock. Rings, Springs and Diaphragm look good and act as they should. This part is under the white plastic part behind the switch and is supposed to push out on the plunger when set to Prime. The part got twisted up and no longer worked. I'm would like to bend it back to its proper shape as I believe this will allow the petcock to function normally. Unfortunately, I can't find any pictures of what it is supposed to look like outside of the device. Anyone have any photos of this? Would like to try before buying a new assembly. -Thanks

[tom203]

"The part got twisted up and no longer worked. I'm would like to bend it back to its proper shape as I believe this will allow the petcock to function normally. "

Yeah, so you plan to retwist it and figure/hope it will be ok. Why bother, just get new one for $60 and eliminate the petcock as source of future problems.Have no fear, there will be plenty if other stuff to fiddle with.

[Steve]

It's not too far from correct right now.

The 'arch' that is shown in the middle appears to be a little higher than normal, but it's pretty close.

.

[AdamW]

It's not too far from correct right now.

The 'arch' that is shown in the middle appears to be a little higher than normal, but it's pretty close.

.

Then I guess it's a matter of orientation at this point

[Cyrano]

I had to do the exact same thing on one last year (can't remember what bike it was for though) and I just sat with all the bits in my hand, laying them up against each other until I worked out what shape it should be to work properly. All I can remember is that it wasn't easy and I wished I had never started it.

As Steve says, it looks near enough as it is so I would give it a go and be prepared to start again. Good luck.

[JEEPRUSTY]

Man that is a vicious little spring.
Very hard to put back in once its out.

Next time do not remove it.

[Nessism]

Agree with the others about the spring. I'd put it in the way it is and tweak from there.

be sure to replace the small O-ring that goes on the end of the diaphragm plunger.

[Murphy Chow]

Did you ever figure this out? I had the same problem, my petcock didnt have any gas flow on any of the 3 settings. the plugs were dry and when it did start id snap the throttle and it would starve itself out.

[tom203]

Don't waste your time fiddling with petcock, get new one for about $50 .

[JJ]

^^^ What he said. Then go for another 30-35 years.

[AdamW]

The good news is that I figured out the orientation of the spring. The bad news is that it snapped when I tried to remove it to give it a final tweaking. Admittedly, I got in a hurry and should have been more careful removing it but i had also probably stressed it pretty hard with the trial and error. The prongs should go in face down. At the bottom of the hole are two square recesses and a recessed ring around wall at the bottom. The outer band of the spring fits into this outer ring. The shortest prong sits in one of the square recesses, the longer one sits on top of the center button that is part of the diaphragm. The spring doesn't have to be bent as much as shown in the original pic. I flattened it out on that final try and was going to give it a slight bend up so that it would have about a fourth of the rise as the original picture shows. The plastic part of the switch rides along this inner ring and should be on PRI when over the center button. I think its worth a shot to try and fix. Just never been documented. Fortunately, you can purchase a new assembly if needed.

[Murphy Chow]

I just took mine apart and it looks are bent as yours I havent yet taken it out. Can you tell me how it all goes together with the plastic piece in place. Ive read what you said in your last post but I would like to know which way the plastic piece goes in my plastic piece has 2 holes one bigger than the other which way did you have it, cant seem to visualize it from your description? I figured out why mine doesnt work, I dont have the spring behind the lever that selects prime/on/res. Anyway I can get a some measurements on that spring. No wonder it doesnt work........Are you going to rebuild this petcock?or just go buy a new one? Was it working when you finished rebuilding it? What rubber o-rings did you use? Im using the harbour freight set thats gas resistant.

Thanks again!

[AdamW]

Did you ever figure this out? I had the same problem, my petcock didnt have any gas flow on any of the 3 settings. the plugs were dry and when it did start id snap the throttle and it would starve itself out.

Assuming you isolated the problem to this device and it is the same as mine, you can figure out the orientation by first aligning the plastic to the switch. The slot for these is keyed so there should only be one fit. The wide end of the slot facing the left should be facing left when pointing to PRI. You can confirm by looking at the labels on the outer snap on metal cover. This should line it up for you if you have the spring installed correctly. In the end, to test, I was able to blow into the main tube when set to PRI and had free flow of air. The other settings had a bit of air passing through indicating that I needed to bend that center part up a bit so that it's not applying so much pressure on the diaphragm button when on the other setting. It was at this point that I got in a hurry and broke the spring when trying to remove it again. Had to buy a new unit since you cant purchase that spring alone. Would rather have fixed than spend another $50. The rest of my petcock was solid to include the oring.

-Adam

[fadingfastfc]

Thank you so much for this! I've got an 81 GS1100 with a rusty tank. I took the petcock apart to clean it, and couldn't figure out this round spring piece inside. You saved me a ton of time!!! I appreciate it.