petcock "on" position?

[Anonymous]

I'm the proud new owner of a '78 GS1000 and the sunny weather here in Portland was a fantastic way to spend the first day with my new ride. It didnt' come with an owner's manual and since I just picked it up last night I don't have a Clymer book yet. The petcock is really oddball, not at all what I was expecting. I thought at first that it was broken since there was no switch like I'm used to. Would someone be kind enough to tell me where the on position is on this thing? Here's a photo of mine.

Is one of those dots on and one reserve or does this petcock only have prime and on? Thanks in advance! [/url]

[Anonymous]

Hi, welcome to The GSR. That petcock looks like nothing I've seen before. I was under the impression that all original GS petcocks had 'On' and 'Res' and that some had 'Pri'. Since they're vacuum petcocks, there's no 'Off' position though. However, some only have On and Res, like mine, which now has a "new" off position since the diaphragm was leaking. Can you adjust that petcock? It looks like the lever may be broken off or something. I don't have a picture of mine, or I'd post it for you, but I'd guess that you're missing something there.

[Anonymous]

Yeah it's adjustable with a small flat screwdriver. It looks for all the world like there's a piece missing, especialy since it's marked PRI but there's nothing else. I thought I read that there was one or two years that did have a petcock similar to this but as I'm still getting familiar with the GS it's a bit of a mystery to me.

[Anonymous]

Bob, if you need a screwdriver to adjust it, it's broken. You should be able to ride you bike, start to run out of fuel and adjust it to res. So if you can't do that, it's broken. Like I said, I just worked on mine, and when I had it apart there was a metal cover that looked like this:
(ignore the dots, it won't let me leave spaces)
.......Fuel
Res..........(new "off" pos)
........On

I'm guessing the ones with prime look something like that, I think the bumps might be just for the lever to snag up on, so that the holes inside line up. I would look into getting another petcock or trying to fix that one, but if you're missing parts, you're gonna need a new(used) one anyways. G'luck!

[SqDancerLynn1]

It's not the original petcock, some of the petcocks in 81? 82? did not have a lever. Just the screwdriver slot

[saaz]

That is not a 78 GS1000 petcock..I have one! The early GSs had a vacuum petcock with prime (on regardless of engine vacuum), on (only flows petrol when engine running) and prime (reserve, but only when engine running. The later models had petcocks like the GSX1100. I think they only stayed on 'On" and needed a screwdriver to change. The one you have looks a bit odd tho even compared to these.

[Anonymous]

bah! As it turns out mine has just decided to go completely TU. I'd just put everything back together with smaller jets, ready to start the butt dyno, and discovered there was no fuel getting to the carbs. Since the petcock was already suspect due to fuel not flowing freely on PRI I took it apart. Inside I found two little flat piece of brass, which used to sit over the diaphragm, were broken off. Now gas just dumps out regardless of where the petcock is set. Looks like time to buy a new one. :x :x :x

[Anonymous]

That looks like the pet cock from an "80" GS 1100, I think the "80" GS 1000 E had them too. One of the dummer idea's Suzuki had back then. No reserve, & no lever. Point the slot straight toward pri. for fuel to flow without vacum. I think "81" & newer went back to on, res., & pri. with a lever to select with.

[Anonymous]

Well the question of whether or not it's from a '78 has definitively been answered. The petcock kit I just got home with isn't for what's on my bike. I'm just gonna suck it up and call Pingle tomorrow and see if they can have one to me by the weekend. It seems that I can't buy a bike that doesn't have to be monkeyed with just to be ridable. This is so frustrating.

[frosty5011]

That petcock is the same as that which I have on my '80 GS850L. No matter how much I played with it using a screwdriver, I never could get the PRIME function to work.

However! Out of all GS's I've played around with (4 of them - I know that's not many compared to other members on the site), I have to admit that this is the only style vacuum petcock that has NEVER given me (or the previous owner) any sort of problem whatsoever. It seals 100% when the engine is off, and I've had this bike for over 4 years. When I have to use the PRIME function, which is only once in Spring, after storage, or after I've done a carb cleaning, I suck on the vacuum hose to fill the float bowls with fuel.

[Anonymous]

I'm wondering, is there something else in this petcock that can go bad other than the diaphragm and such? My thought is something in that oddball little PRI/ON screw mechanism thingy has gone south, preventing the whole thing from working properly? As it turns out I think I have the correct rebuild kit after all. I was a little confused since the diaphragm in the kit doesn't look exactly like the old one but it's supposed to fit 78-81. Anyway the fuel filter appears to be clear and I can feel some suction when I put my finger over the vacum line while cranking. No gas is flowing. The carbs are properly seated and everything looks tight, I don't *think* I missed anything.

[Anonymous]

mine is just like your pic (1980 gs1100et). i thought it was very strang not to have a lever. i ordered a new one, etc. the new one was the same, no lever. very wierd of suzuki.