Quick Petcock question

[Gregory]

haha ya unless whoever installed the petcock did so with a reserve even if the tank didn't have one. Though I just went out and tried turning it with the screw. There's no apparent stopping point to it. It just keeps turning and turning and turning.

The petcock IS what creates the reserve. The main filter tube has a starting point higher in the tank than the reserve tube.

[koolaid_kid]

If your petcock has a slot instead of a handle, which means it does not have a reserve position (and the associated dual tube system inside the tank), and it rotates a full 360 degrees, I suggest you find out where the slot should reside to select the PRI and ON positions.
This is how to do it:
You are concerned about 4 positions: 0 degrees (or straight up and down), 90 degrees, 180 degrees and 270 degrees.
Unplug the vacuum tube (the smaller of the two) and the fuel line (the larger of the two).
Place the fuel line in a catch can or jar. Rotate the slot to each position and check to see if fuel flows without applying a vacuum to your vacuum line. If it flows, this is your PRI position(s).
Now go 90 degrees clockwise/counter clockwise from that position. Fuel should not flow. Put a vacuum on the vacuum line (just sucking on it will perform this function). If fuel flows this is the ON position(s).

[Steve]

If your petcock has a slot instead of a handle, which means it does not have a reserve position (and the associated dual tube system inside the tank), and it rotates a full 360 degrees, I suggest you find out where the slot should reside to select the PRI and ON positions.
This is how to do it:
You are concerned about 4 positions: 0 degrees (or straight up and down), 90 degrees, 180 degrees and 270 degrees.
Unplug the vacuum tube (the smaller of the two) and the fuel line (the larger of the two).
Place the fuel line in a catch can or jar. Rotate the slot to each position and check to see if fuel flows without applying a vacuum to your vacuum line. If it flows, this is your PRI position(s).
Now go 90 degrees clockwise/counter clockwise from that position. Fuel should not flow. Put a vacuum on the vacuum line (just sucking on it will perform this function). If fuel flows this is the ON position(s).

Gonna have to modify that just a little bit, K_K.

On those petcocks, PRIME does not free-flow when you put the petcock into that position, it takes a brief application of vacuum (what I called a 'puff' earlier) to get it going. However, it will keep going when the vacuum is released.

So, ... the test should be:
Fuel line into a jar, vacuum line available so you can suck on it. Rotate the petcock slot straight up and down. Suck on the vacuum tube for two or three seconds, gas should flow. Stop sucking. If the gas also stops, that is your RUN position. If it keeps flowing, it is your PRIME position, but check the other position anyway. Rotate the slot sideways. Suck on the vacuum tube, gas should flow. Stop sucking. The gas flow should be the opposite of what happened in the first test.

I don't have one of these blessed critters so I don't know which position is which, I may have mixed them up, but your testing will tell you for sure.

.

[koolaid_kid]

I don't have one either, and I am also glad for the fact. Thanks for the clarification, btw.
We had a new member come on with the same issue (360 degrees of rotation) but he got really ticked off and left before I could explain how to test which setting was which. Pretty basic, really, although I am glad Suzuki realized their mistake and only put that petcock on (1?) year.

[JaNewb]

haha he got ticked off and left? I just figured it out myself. Patience is hard to come by these days. He just bought a really expensive lawn ornament.... I forgot to check this thread and just figured it out logically. The never ending turning was a dead give away that the position was what mattered. Anyway, so I just came back from testing it. Ran the test exactly as described in every way possible and it doesn't look like my petcock is working. The run position works in both cases but my prime doesn't seem to be working. Even hit it with my hammer a few times to try getting something loose but no luck.

[JaNewb]

Is the petcock dependent on the vacuum system or can I just buy any petcock with 50mm bolt spacing and block off the vacuum if the petcock isn't vacuum operated?

[Agemax]

Is the petcock dependent on the vacuum system or can I just buy any petcock with 50mm bolt spacing and block off the vacuum if the petcock isn't vacuum operated?

correct, yes you can do it that way....

[Tom R]

If you want to do away with the vacuum feature, a cheaper way is to remove the spring from under the diaphragm - so it will free flow - and add an inline valve.
The downside is, if you forget to turn it off overnight, you'll flood your crankcase with gas.

[JaNewb]

Thanks! I'm always second guessing myself because I'm new to working on bikes.

[BassCliff]

Hi,

Many riders will replace the stock vacuum petcock with an aftermarket Pingel unit, just ON, OFF, and RES. You must block off the vacuum port on the #2 carb that feeds the stock petcock. You must also never forget to turn off the petcock every time you stop the engine.

I find it amusing that this "Quick Petcock Question" has gone on for 25 posts.


Thank you for your indulgence,

BassCliff

[JaNewb]

Hi,

Many riders will replace the stock vacuum petcock with an aftermarket Pingel unit, just ON, OFF, and RES. You must block off the vacuum port on the #2 carb that feeds the stock petcock. You must also never forget to turn off the petcock every time you stop the engine.

I find it amusing that this "Quick Petcock Question" has gone on for 25 posts.


Thank you for your indulgence,

BassCliff

Ya seems like most of my posts end up this way. lol i always manage to say or create something amusing.

Thanks for the advice cliff!

[eil]

I think you already have your questions pretty much answered, but if you Suzuki's official word on this petcock, go to BikeCliff's site, download the GS850G shop manual, and have a look at page 336.

Probably better off just buying a new petcock, though, if you can swing it.