fuel petcock GS750T

[painter]

Hi, I have a question about the fuel petcock on my 1982 GS750T. The only time i can get fuel to come out is if i put it on reserve. Has any one had this problem or is it no big deal.

Thanks Painter

82 GS750T

[Steve]

Are you sure you are reading the markings correctly?

When the lever is pointing forward, you are on REServe.
When the lever is pointing down, you are in the normal ON.
When the lever is pointing rearward, you are in PRIme position.

In the PRIme position, fuel should flow freely. In order for fuel to flow in the other positions, vacuum has to be applied to the smaller hose on the back of the petcock. This is usually done by running the engine. If, however, the engine does not open the petcock, the valve might be stuck. You can disassemble the petcock to see if the valve is stuck. One other possibility is that the diaphragm has a hole in it, preventing proper operation of the petcock. Replacements are available, but many here have found them to be of questionable quality. You will find very vocal proponents for replacing your 'junk' vacuum petcock with a manual unit (usually a Pingle), but many of us will recommend sticking with a new vacuum unit.

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[BassCliff]

Greetings and Salutations!!

Hi Mr. painter,

You're new here, aren't you? That's OK, I was new once too. Now I'm just a pest.

As Mr. Steve says, these are vacuum operated petcocks. The circle on the end of the lever is where the petcock is set. Check out this little page:

Where Do These Hoses Go?

Now let me roll out the welcome mat for you...

Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures (bigger pictures)! Not you, your bike!

Thanks for joining us. Keep us informed.

Thank you for your indulgence,

BassCliff

[Steve]

The circle on the end of the lever is where the petcock is set.

Gotta be careful with that, Cliff, not all petcocks have a circle. Here are pics of my wife's petcock on an '82 850L:







.

[painter]

Thanks guys i'v never owned a Suzuki be for. I'v owned kawi's. I have never seen a petcock like this before. Would it cause any engine performance problems depending on where you set the petcock?

Thanks Painter

[Griffin]

Thanks guys i'v never owned a Suzuki be for. I'v owned kawi's. I have never seen a petcock like this before. Would it cause any engine performance problems depending on where you set the petcock?

Thanks Painter

So long as there is enough gas in the tank, theoretically, no. Leaving the petcock on "prime" without the bike running is asking for trouble though. Fuel will fill your carbs, and if your fuel shotoff valves inside the carbs don't seat and seal 100%, you'll find a bunch of gas on the floor (and in your engine) in the morning.

[Larry D]

You have four options.

1. Leave it how it is and ALWAYS remember to turn your petcock off when you turn off the bike. And conversely turn the petcock to prime when you ready to ride.

2. Rebuild the petcock with kits available at numerous part sites. Members here have reported varied results with this option.

3. Get an aftermarket petcock as stated above. This will be basically option 1.

4. Get an OEM petcock and not worry about it for 20 years or so. This is the option I recommend.

[gustovh]

If you are not getting gas in the vacum line to the fuel valve, you don't need a kit.
Remove the valve from the tank.
Loosen the 4 screws on the back of the valve until they gap.
Give the back of the valve a rap with a screwdriver handle to break the seal.
There is a spring inside, so hold both halves and remove the screws.
Seperate the halves and remove the diaphram inside.
There is a 6 mm O ring on the valve spud, replace it with a new one.
In the valve body, look at the seat for the O ring, it will probably be corroded. It needs to be cleaned and smooth. You can make a mandrel out of aluminum rod, about 3/8 dia. Chuck up a pice of the rod a couple inches long in a hand drill and useing a file match the taper of the seat. Now useing an abrasive such as brasso or silver polish, recondition the seat untill uniformly smooth.
Clean out the valve body of any gunk/rust or debris.
Reassemble.
The valve should not leak and should function properly.
Just my 2cents.
You have a plugged gas valve.
V