1980 GS 850 GL petcock

[Anonymous]

I am new to GS's and relatively inexperienced with motorcycles overall. My 1980 GS850GL has a vacuum operated petcock. there is no lever just a port with what looks like a plastic flat-head screw in it. On the body of the valve there is a Fuel position at the 12 o'clock position and PRI at 11 o'clock. I tried adjusting the screw with the fuel line running to a tank and could seem to find the prime position. How does this thing work and how do I prime my carb. I stopped messing with it because I was afraid of stripping the plastic screw.

[Redman]

I have an 80 GS850G that has a lever, so I cant answer from personal expereinece. But....

My Suzuki factory manaul has a section for the "fuel cock" on the L. It shows screw slot like you mentioned, but shows the ON position is horizontal (parrellel with tank bottom edge) and the PRIme position is vertical.

You are talking about 11oclock and 12 oclock, so maybe you are not turning it far enough.

I could email you a copy (PDF? JPG?) of that page if you would like. (Use the PM and give me your email address)

Welcome to GSR.

[Anonymous]

Does your petcock look kind of like this?



I bought one of these last summer from Cycle-Re-Cycle 2 to replace the leaking/busted petcock on my 1980 GS550L. It isn't a very intuitive design; after various trials and tribulations I figured out that ON is when the slot is horizontal, and PRIME is when the slot is vertical (pointing at the V indicator). At least, that's the way it works on the one I bought. The "PRI" isn't really at the 11 o'clock position, it is next to the V to indicate what aligning the slot with it will accomplish. The vacuum activated fuel flow works when the slot is aligned horizontally and the engine is running. If you leave it vertically it will continuously flood your carb bowls, resulting in the dreaded varnish-effect. Hope this helps...

...Ross

[Anonymous]

the fuelcock I have looks exactly like the picture. I still can't get fuel flow no matter what position the screw is in. Any ideas. Thanks for the help.

[Jackrp]

Re: 1980 GS 850 GL petcock

I am new to GS's and relatively inexperienced with motorcycles overall. My 1980 GS850GL has a vacuum operated petcock. there is no lever just a port with what looks like a plastic flat-head screw in it. On the body of the valve there is a Fuel position at the 12 o'clock position and PRI at 11 o'clock. I tried adjusting the screw with the fuel line running to a tank and could seem to find the prime position. How does this thing work and how do I prime my carb. I stopped messing with it because I was afraid of stripping the plastic screw.

Put the slot verticle, apply vacum,(turn over motor, or put a hose on the vacume port to the petcock and suck for a sec)this will open the petcock, to stop the flow of gas put the slot horizontal, this allows the petcock to close as long as no vacum is present, this petcock has caused me more grief and as such have become a petcockogoligist(GS850LT).

[Anonymous]

Are you trying to get fuel to flow with the slot in the horizontal position without the vacuum tube connected or otherwise attached to a source of vacuum (e.g., mouth suction)? When in the vertical position, fuel flows freely with or without vacuum. When in the horizontal position, the petcock is designed (when working properly) to allow fuel to flow only when there is a vacuum at the carb end of the vacuum tube (i.e., only when the engine is running, or your mouth is puckered 'round the tube). With residual gas typically left in the float bowls, there's usually enough to fire up the engine and get the vacuum established; if not, well that's why there's a Prime position. If you have attached the vacuum tube correctly (goes to one of the carbs, don't remember which), and you are still not getting flow with the slot in the horizontal position, then either the vacuum tube is clogged, or the inlet at the carb is clogged, or the petcock is broken, or the carb is not functioning properly . Not being much of a motorhead, those are the only suggestions I can come up with, and I would attack fixing the problem in that order. Maybe others on the site have some more ideas. Good luck.

FWIW, the petcock I purchased last year from CRC2 has been working like a champ. No affiliation just a satisfied customer yada yada...

...Ross

[Wingnut]

Re: 1980 GS 850 GL petcock

[quote="Jackrp
Put the slot verticle, apply vacum,(turn over motor, or put a hose on the vacume port to the petcock and suck for a sec)this will open the petcock, to stop the flow of gas put the slot horizontal, this allows the petcock to close as long as no vacum is present, this petcock has caused me more grief and as such have become a petcockogoligist(GS850LT).[/quote]

I have the same one and have not figured it out either. Are you saying that if you turn it to prime, it won't prime until some vaccume is applied, and once the vaccume is applied and removed, it will continue in the prime mode until switched back to normal? This may make sense because I could not get any fuel out of mine by turning that screw. And turning that screw. And turning that screw. So the procedure must be if the carbs are dry, turn the petcock to prime, crank the engine for a few seconds to open the valve, waite a minute or two for the bowls to fill, then attempt the start?????????????

I did get my carbs primed by sucking my head inside out on the vaccume hose for a couple of minutes, and then it worked OK. But I could not understand Suzuki expecting people to do this on a yearly basis.

[Poot]

Ive got a GS850 L *1980*

I keep the slot aligned horizontally, with a little triangle on the left side.

You may need to keep it on prime to get more gas to start it?

[Jethro]

Buy a Pingel.