GT vs. later GS petcock => not compatable

[jabcb]

This is a comparison of a single-outlet GT-series petcock to a later-GS-series petcock.
The GS petcock has part # 44300-34470. It was used on several different models from around 1980-1983.

The box shown in the pics has major marks an 1" spacing & minor marks 1/4" spacing.

Bolt spacing looked to be the same.

Pic of GT-series petcock.
Distance from outer edge of mounting surface to end of vacuum chamber about 1-3/4"
Has gap between vacuum chamber & box.


Pic of later-GS-series petcock.
Distance from outer edge of mounting surface to end of vacuum chamber about 2-1/4"
No gap between vacuum chamber & box.


Pic of later-GS-series petcock showing how far vacuum chamber extends beyond mounting surface.



This petcock doesn't look usable on our GT-series tanks.
But some early-GS-series petcocks look different & may work out.

[Coyote]

The GS petcock on my 78 1000 is identical to the GT petcock except the vacuum back is square. The mounting holes are also the same spacing. I have a pic of it somewhere. I'll post it up if I find it.

[Coyote]

Bolts right on. Other than the vacuum in and the fuel out -- definitely usable. This is a 78. I believe 79 was the same. The lever side -- they look alike.

[mikefealk]

funny i see this post now, just took the petcock of to rebuild on my tank and realized it was not the original petcock. the p.o. had hammered down the seam on the tank next to the petcock to make clearance for what i now believe is a gs petcock. bent the seam right over. after looking over every part and piece by now it seems his only shop tools were a bfh and a crowbar.

[jabcb]

Ouch, that early GS petcock is expensive.
Just checked. The early 3-outlet GT petcock & the early GS petcock now sell for $300+

The single-outlet GT petcock now sells for $100+
That's reasonable considering that a Pingel vacuum petcock is around $170

Prices for single-outlet GT petcocks may start to climb, so I was hoping a GS petcock was an alternative.

[Suzukidave]

I wonder if this is why some of the GT's came with a spacer between the petcock and the gas tank ?