Petcock. Vacuum to Manual

[Coyote]

The petcock on my GS1000 is giving me fits. Internally it's the same as the GT petcocks. I bought a rebuild kit with new everything and it still leaks. The only thing I can think is the o-ring groove is out of round -- making the o-ring itself out of round. I've had it apart about 15 tines with no results. With it apart, I can press the o-ring on it's seat with my finger and press really hard. I can still blow air through it from the outlet hole. The o-ring seat is immaculate. I have looked it over under 10 power magnification and it's flawless. Still, it won't seat.
I've had it. It worked great for nearly 20 years and now it won't work at all. I've been through and repaired several petcocks so they are no mystery to me. The new diaphragm came with it's pintle installed and a new o-ring. All that is new. 4 hole gasket is new. V seal on the lever is new. These is no reason why it won't seal.
Is there a way to convert these petcocks to manual? On-off-reserve? If not, I'm going to get a manual petcock from Parts-n-More.

[tricky1962]

I converted my T500 petcock to on-off-reserve (losing prime in the process). I don't know if they are the same design, but I took the side plate off and plugged the hole the fuel went down when the tap was on prime. I plugged the hole with a bit of rubber tubing, so it is reversible if necessary.

It takes several kicks to start if the carbs are empty, but doesn't leak

[ConnerVT]

What is the difference between "Prime" and "On" or "Reserve"? All just mean that gas will flow to the carbs unrestricted.

[Whit]

On and Reserve will only let fuel pass with a vacuum. Prime requires no vacuum.

[ConnerVT]

I thought Tricky modified it, as many do, to eliminate the need for vacuum. Basically converting it to a manual petcock. I guess the way he did it works as well.

After fighting with 3 different Suzuki petcocks, spending $$$ on parts, and hours of playing in gas, I've decided it isn't worth it (unless doing a 100% restore). For a bike you're going to ride, buy a decent manual petcock. I am so much happier, now that I replaced the Suzuki (and Chinese junk) with a Pingtel.

[Coyote]

I think you guys are missing the point. I just want to know if I can somehow convert this vacuum petcock to a manual. If so, how? I saw a post about it a long time ago. If I remember right, it had something to do with blocking the cutouts on the back of the lever.

[tricky1962]

I plugged the prime route to give me an off position as the tap leaked slightly at "On" and "Reserve". I still need vacuum to get good fuel flow.

If you want a completely non-vacuum set-up, I believe you have to replace the diaphragm with a sheet of rubber.

Check out the post at the bottom of the page

http://www.vjmog.com/ftopict-8398-t500.html+petcock" onclick="window.open(this.href);return false;

[bill in okc]

Maybe not a solution here but this link has become standard procedure when I rebuild a petcock. It works well and the lever gets easier to turn.

http://www.xs11.com/forum/showthread.ph ... ck+surface" onclick="window.open(this.href);return false;

[yeadon_m]

Coyote,
I gave up with leaks on mine and have fitted an in-line on/off fuel tap on all 3 GTs I have. The OE taps aren't bad on leaks but if sat for a few weeks between rides, the carbs can dribble.
One thing you might try is to slightly elongate the spring behind the diaphragm. They can take a squashed set over the years and not press the O-ring home quite so well. Careful not to over do it or the vacuum won't be sufficient to lift and uncover the fuel hole!
Cheers,
Mike

[Coyote]

Bill, I already do everything listed in the thread.
Mike, I had a longer spring from another petcock. Nearly twice as long. Still didn't/won't seal.

[rngdng]

I remember someone posting a way to convert it (years ago), but I can't remember. It did involve tapping and plugging a port in side.


Lane

[Coyote]

OK guys. This is not rocket science. Here it is. Keep in mind that this thing worked flawlessly for 18+ years. When it first started leaking, I took it apart to find that the o-ring I used had swelled so much that it was no linger entering the taper. This o-ring was not the original. We had a huge assortment of o-rings at work and we tried several till we found on that would seal. It was red. Why it took 18 years to swell up, I have no idea. I didn't want to face that problem again, so I bought a rebuild kt that included the o-ring. So it's pretty much all new guts



Hard to take a close up without shadows, but you can see the seating taper is in fine shape. No flaws even under 10 power magnification.



Just now I got out my calipers and started checking to see if the new o-ring was actually reaching the seat. Yes. Then I flipped it over and think I may have found the problem. Hard to photograph without shadows, but the o-ring is not hitting the seat square. It's cocked to one side. The metal end seems to be hitting on the taper - not allowing the o-ring to seat. This tells me the plunger is not centered in the new diaphragm. I can't think of any other reason that this could be happening. Stupid me, I threw the old diaphragm away. I don't think there is any fix.

[rngdng]

Cheap rebuild kits.....Keyster perchance?


Lane

[Coyote]

No. K&L Japan made