Dumb question time - why do we GS'ers need a vacuum petcock?

[80GS850GBob]

Dang...lets all relax a little....it was just a dumb question on my part...definitely not worth arguing over.

My observation was simply why the suzi system needed a vacuum stop as opposed to all the other brands that don't over flow unless a needle and seat goes bad.
My hondas and kawis didn't need it...just wonder what the difference on my suzis was.

 

[GS1150Pilot]

They don't 'need' it, it is just so that riders don't have to remember to shut off a manual petcock after their ride is over. Personally, I prefer the simplicity of a manual petcock but lots of riders don't like having to remember anything so they prefer the no brain required approach of a vacuum petcock.


Mark

The simplicity and flow of a Pingel is a wonderful thing.

 

[jsandidge]

Wrong. The worst thing that can happen with a damaged diaphragm is fuel being sucked in while running. No full crankase or hydrolock issues. When off, the fuel is blocked from free flowing into the vacuum port. The problem you're describing is typical if you leave any manual petcock on or leave the vacuum operated one in prime.

If you have a weak spring behind the diaphragm or a bad o-ring, you can definitely get a full crankcase. I just fixed this issue on my 83. I never experienced hydrolock with it, but I never tried to crank it until I fixed it. The PO reported hydrolock to me though. My diaphragm was porous too, and fuel definitely could pass from the "wet side" to the "dry side".

 

[Guest]

I am going to guess that the "original design" never made it to production, or maybe it was never released on bikes destined for the US market.

I have never seen a double diaphragm or a one way valve on ANY bike, whether it was Suzuki, Yamaha, Honda or Kawasaki.

Yeah, my observations have been limited to those that were sold in the USA, so I don't know what was offered to the rest of the world.

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Seriously? Those are all they had on GS until 1980. The big original clunky one with the screw on lever retainer.

 

[80GS850GBob]

The simplicity and flow of a Pingel is a wonderful thing.

I'd add this...aside from making the action of working a pingle along with an ignition key for start up and shut off of the cycle, one could consider it a poor mans anti theft...

 

[Gorminrider]

Does anyone make an electrically operated one? It would seem to prevent some of the issues with the vacuum style and would make priming it easier when the bowls have emptied out.

I think some bikes use vacuum-operated pumps. some Yamahas..xv250 for one. Looking at its parts fiche, I assume the tap itself is "simple".

 

[80GS850GBob]

I think some bikes use vacuum-operated pumps. some Yamahas..xv250 for one. Looking at its parts fiche, I assume the tap itself is "simple".

Snowmobiles do...they operate on the vacuum pulse. Only thing I'd question is that the application there is two stroke and this would be for four stroke..should work better....

 

[GS1150Pilot]

I'd add this...aside from making the action of working a pingle along with an ignition key for start up and shut off of the cycle, one could consider it a poor mans anti theft...

Agreed, and since I relocated my key to the same area, it's a one-two process to put the key in and switch the fuel on.