Fuel tap mystery

[abgill@telus.net]

hey all,
My bike had a bastardised fuel tap off a mower mounted on it when I acquired it recently, so I bought a new vacuum tap and after fitting it, realised that the handle isnt included in the deal. I checked assorted fiches and the handle [with the round indicator hole] is nowhere to be found.
Anyone lead me in the right direction please?????
Al

 

[abgill@telus.net]

heres some photos just after I acquired the bike

 

[steve murdoch]

Hard to tell from the pic but it sounds like you might have the "dreaded 1980 petcock".
Steve explains the operation in this thread.
https://www.thegsresources.com/_for...-shut-off-question&highlight=1980+and+petcock

Low mileage bike you have. Is that a stainless MotoGP exhaust?

 

[Steve]

Yep, even though you have given us only one clue to what bike you have (a 16-valve 1100, either '80 or '81),
the petcock in use tells me that it's an '80.

There is no "handle" for that petcock, just a screwdriver slot.

And, ... are you ready for this? There is NO RESERVE function.

Hope your fuel gauge works well. :-\\\

.

 

[abgill@telus.net]

fuel tap woes

fuel tap woes

Yep, even though you have given us only one clue to what bike you have (a 16-valve 1100, either '80 or '81),
the petcock in use tells me that it's an '80.

There is no "handle" for that petcock, just a screwdriver slot.

And, ... are you ready for this? There is NO RESERVE function.

Hope your fuel gauge works well. :-\\\

.

yes indeed its a GS1100 4 valver 1980....
So I fitted the new tap and now the bike runs on the prime setting just long enough to drain the bowls and then it stops......
Wait a few minutes and it starts again, runs for a minute or so then stops....bugger me.......
Ill put a fuel line on the tank and see what happens when I just let fuel run with the tap on prime and see how long it goes before something happens.....gggrrrr.......

 

[abgill@telus.net]

Hard to tell from the pic but it sounds like you might have the "dreaded 1980 petcock".
Steve explains the operation in this thread.
https://www.thegsresources.com/_for...-shut-off-question&highlight=1980+and+petcock

Low mileage bike you have. Is that a stainless MotoGP exhaust?

Actually I thought it was 47000km, not 4700.............ha!
Does anyone know of a simple on-off option rather than the silly vacuum system? I have seen some taps that have a clip-on handle, but every bike I checked at the local wreckers was the same as mine. It must have been a different model perhaps.

 

[Steve]

Think what you will of the "silly vacuum system", but I prefer it. I have used one for so long, I would forget to turn one on and off, as necessary.

Now, if you have grown up with nothing but on/off valves on dirt bikes and other older bikes, you would be accustomed to turning it. One often-recommended valve is made by Pingle. Be careful when shopping, as your petcock has different bolt spacing.

.

 

[Baatfam]

Does anyone know of a simple on-off option rather than the silly vacuum system?

One often-recommended valve is made by Pingle. Be careful when shopping, as your petcock has different bolt spacing.

A few words about the Pingels. Yes they work, and they look very nice. But having had them on two different GS bikes, (one I still have), a few words of caution.

1. They actually cost the same or more than stock...Around $100

2. You will forget to turn it off one day and have a case full of gas...happens to everyone I know that put one on.

3. After 8-10 years they WILL start to leak. Stock should go for 20-30 years or so. (Supposedly, you can send the Pingle in for a rebuild, but I don't know for sure.)

To be fair, I just put a new one on my GS1100E, it works fine, and looks great.

 

[Tom R]

Even on prime, that petcock needs a bump of vacuum to get it open. The difference is, when the barrel is turned to prime, it blocks off an air bleed and the diaphragm will theoretically hold open after after the vacuum source is removed (at least for a while); and in the run position, a small air bleed is exposed that will let the spring push the diaphragm closed after the vacuum source (like an running engine) is removed.
Did you get an aftermarket or OEM replacement?
I bought an aftermarket one years ago that gave me nothing but headaches.... I eventuall replaced the spring under the diaphragm with the OEM spring from the old petcock.... kinda worked.... but would still decide to flood the crankcase with fuel at least once a year. Usually after a fresh oil change.
Now I have a 5/16 inline fuel valve.
Buying a cheap petcock over the OEM was some of the worst money I never spent.

 

[Nessism]

The factory service manual (available for free download from Basscliff's website) details how the factory petcock functions. As mentioned already, in order for "prime" to function there needs to be some vacuum to initially pull it open, then a check valve embedded into the back cover holds it open.

I also bought an aftermarket petcock, which incidentally looked identical to the OEM petcock, only the check valve never worked. Sprang for a new OEM petcock and all was good after that. If there is only intermittent fuel flow that could be a petcock issue or possibly a venting issue (through the cap). I'd check all possibilities just to be safe.

 

[abgill@telus.net]

Its a real Suzuki petcock

Its a real Suzuki petcock

The factory service manual (available for free download from Basscliff's website) details how the factory petcock functions. As mentioned already, in order for "prime" to function there needs to be some vacuum to initially pull it open, then a check valve embedded into the back cover holds it open.

I also bought an aftermarket petcock, which incidentally looked identical to the OEM petcock, only the check valve never worked. Sprang for a new OEM petcock and all was good after that. If there is only intermittent fuel flow that could be a petcock issue or possibly a venting issue (through the cap). I'd check all possibilities just to be safe.

YES its a real Suzuki petcock, $150 at the Suzuki dealer. Im looking at fuel flow this morning. Im also contemplating pulling the carbs......

 

[abgill@telus.net]

so does the last digit on the speedometer read in KM's or 1/10ths of km, so the mileage shown at 4507.7 would either be forty five thousand and seventy seven, or is it forty five hundred and seven and seven tenths? Just asking. The bike certainly appears to be well past 4500km, thats for sure.......

 

[Steve]

so does the last digit on the speedometer read in KM's or 1/10ths of km, ...

The picture you posted earlier shows four thousand, five hundred twenty five and seven tenths kilometers.

How much have you ridden since that picture? :-k

.

 

[abgill@telus.net]

The picture you posted earlier shows four thousand, five hundred twenty five and seven tenths kilometers.

How much have you ridden since that picture? :-k

.

my apologies, thats the numbers on the speedometer....I cant get it to run so no extra km's....
Boy it sure looks and feels like a 45000KM bike, or the previous owners were just animals........
It was a 'barn find' so I guess ultimately nothing surprises me......
4525.7 km would sure be nicer than 45257 km for sure.
Al

 

[abgill@telus.net]

I have to get back at it before the snow flies, but Im finding it hard to park my 71 CB750 to work on the GS....
What a terrible first world problem to have....!!!

 

[steve murdoch]

Nice looking Honda!
What snow flying? I see 13 and sunny for mid-week Edmonton.

 

[abgill@telus.net]

Nice looking Honda!
What snow flying? I see 13 and sunny for mid-week Edmonton.

Yep, thats this week, next week will be different..........I only got back from New Zealand a few weeks ago and damn I miss those winding roads, half sane drivers, driving on the left..............
I found out what my GS problem was, maybe before I had gotten too excited I should have checked the carbs more closely - stripping the carbs revealed one main jet laying in the bottom of the float bowl, all four pilot jets clogged solid with dead fuel crap and grunge....so its back together tomorrow and off for a blast around the block after lunch when it warms up to a merely toasty 11 degrees or so.
Livin' the dream..........one warm day at a time so they say.

 

[Guest]

Just buy a new stock petcock and go riding. I would buy the Suzuki one, I've tired a couple aftermarkets designed like the stock one, for some reason they didn't last the 20+ years like the factory one. Rebuilding is a gamble too, failure rate is really high on the kits.

 

[abgill@telus.net]

yes indeed

yes indeed

Just buy a new stock petcock and go riding. I would buy the Suzuki one, I've tired a couple aftermarkets designed like the stock one, for some reason they didn't last the 20+ years like the factory one. Rebuilding is a gamble too, failure rate is really high on the kits.

Ok, a dose of common sense and some dedicated time to the cause has solved 99% of my problems.
I pulled the carbs and found that one main jet was laying in the bottom of the bowl. as well I acquired another main jet laying on top of the engine behind the cylinder block, so my guess is the former owner tried to clean the jets, dropped one and then didnt properly install the replacement. Obviously he tried to stuff it up through the drain plug and when he missed the main jet thread couldnt be bothered to retrieve it and fix it properly......
I checked the float height, cleaned everything else, unblocked three pilot jets, soaked everything in dishwasher mix [ a dishwasher tab in a cup of hot water] overnight, stopped the fuel leak from the new hose I had installed and forgot to put a clamp on, reinstalled the carbs and all seemed pretty well with the world in general terms. I reset the camchain, turned the silly fuel tap to prime with my little screwdriver and started 'er up.........Engine sounds very nice, ye har!!!!
Now Im stripping everything and painting the bike and new handlebar fairing in Wes Cooley replica blue and white. New alcantara blue seat cover, tyres and chain and sprockets and colour coded [dark blue] braided brake lines F & R will go on while Im doing the paint.
wish me luck.....

 

[steve murdoch]

Glad you got the carbs sorted even though i am very surprised that something as mild as soapy hot water did the trick.
Your bike so 100% you get to choose how it looks BUT i like black seat covers. Looking forward to seeing how this one turns out.