petcock change...do I need diaphram?

[bothebrave]

First off, let me say I am new to the site and love it! I never knew a cult following for the GS existed.....

Background of the problems....purchased the bike two years ago in garage stored none running condition for about five years. $450 didn't seem like a bad deal, the side airbox cover was missing so used duct tape in attempt to seal the box. Worked well for a couple of days untill pods came in the mail. Purchsed single main jets from local bike shop, cheaper than set.

I have been faced with a few problems, I know the jetting is not right, and only getting about 50 miles per tank at about 38 mpgs. I can only use half a tank or so and 'run out of fuel.' Add fuel and it fires right up. Wondering if I can do away with the diapram petcock and go with a traditional gravity flow. (I did buy a rebuilt diaphram.) If so can I tap both sides of tank in order to use the fuel from both sides since I am only making use of 1/2 a tank.

I know switching to a gravity flow petcock will have continuous flow and will need to be shut off. I don't know why I can not make full use of the whole tank. I am just not sure how the vacum system works and if I can change it. Can someone explain or guide me in the right direction?

Thanks,
bo

[Dave8338]

Welcome to the fourm...Basscliff will be along and give you the welcome you deserve.

In the meantime...If it were me (and many others here) I would just spend the 50-60 bucks and get an OEM petcock and replace it. It is a sfety part and fuel related...buy the real deal. That being said, some have had success with the rebuild kits, but I'm not one of them. Some have replaced the petcock with a Pingle and are very happy with that, but I'm not one of them. I replaced the petcock and have not had fuel in my oil; don't need to rember to shut it off; and it always works the way that Suzuki designed it to work. IMHO

[bothebrave]

Thank you for the warm welcome to the site, I am sure that I will come into contact with more people like you.

By replacing the old petcock with a new one, I will be able to make use of the full tank of gas?

How does the vacuum work on the bike?

[don_gibb6512]

Thank you for the warm welcome to the site, I am sure that I will come into contact with more people like you.

By replacing the old petcock with a new one, I will be able to make use of the full tank of gas?

How does the vacuum work on the bike?

I have an '80 GS1000G and I put a Pingel non-vacuum petcock on it. They also make a vacuum operated one. It sounds like the petcock you have on it now is clogged up or something. You don't need two petcocks. That would just be a mistake. The vacuum opens the diaphragm when the engine is turning over or running. I didn't have much luck rebuilding the OEM petcocks with the K&L kits but some guys do. They're about $26. If you run the original set of carbs, I would suggest either buying an OEM petcock or the Pingel vacuum operated petcock. You don't need the high flow rate that the Pingel non-vacuum provides. 38mpg sounds about right, btw.

Good luck.

[SqDancerLynn1]

Does you petcock have a lever ? You can turn it to the reserve setting when the main fuel supply runs out or to prime. Make sure to turn it back to the on position after fueling up.
Their also could be a lot of junk in the gas tank blocking the intank filter & fuel flow. ? I would clean it as needed

[bothebrave]

I assume you plugged the vaccum line? What happens to the flow of fuel if using a non-vaccum petcock, I assume the fuel would continue to flow into the carbs???

[bothebrave]

Does you petcock have a lever ? You can turn it to the reserve setting when the main fuel supply runs out or to prime. Make sure to turn it back to the on position after fueling up.
Their also could be a lot of junk in the gas tank blocking the intank filter & fuel flow. ? I would clean it as needed

It does not have the lever, and is operated by vaccum. If I go with the lever style petcock I will need to plug the vaccum line and assume that the fuel will continue to flow into the carbs when the bike is not running. Seems as though I should purchase a new diapram petcock?

[Nessism]

The 1980 Suzuki petcock is the one year wonder without a lever. The bolt spacing is unique so you can not substitute a petcock from a different year Suzuki. I don't believe that version of petcock has a reserve, only Prime and ON. You can still get the OE petcock, or there are aftermarket petcocks available. Pringle makes a full manual petcock (not cheap) or K&L makes a copy of the stock petcock. Check Z1 Enterprises for the aftermarket parts or your favorite OE parts source for the Suzuki part (flatoutmororcycles.com is the cheapest most of the time).

Good luck.

[Larry D]

Replace it OEM, or get a Pingle. With the Pingle you cap the vacuum on the carbs and turn the fuel on and off. Most importantly off when you shut off the engine.
Get a new one !! You have +- 5 gallons of extremely flammable liquid, 8 inches from some very important body parts.

Suzuki...good.
Fire....very,very bad.

[bothebrave]

The 1980 Suzuki petcock is the one year wonder without a lever. The bolt spacing is unique so you can not substitute a petcock from a different year Suzuki. I don't believe that version of petcock has a reserve, only Prime and ON. You can still get the OE petcock, or there are aftermarket petcocks available. Pringle makes a full manual petcock (not cheap) or K&L makes a copy of the stock petcock. Check Z1 Enterprises for the aftermarket parts or your favorite OE parts source for the Suzuki part (flatoutmororcycles.com is the cheapest most of the time).

Good luck.

It is god to know that I can in fact plug the vaccum on the carbs in need be. I am hoping to change to a longer tank, purely for looks, so knowing that I can change to the other style of petcock valve without changing my carbs is a relief.