• Required reading for all forum users!!!

    Welcome!
    Register to access the full functionality of the GSResources forum. Until you register and activate your account you will not have full forum access, nor will you be able to post or reply to messages.

    A note to new registrants...
    All new forum registrations must be activated via email before you have full access to the forum.

    A Special Note about Email accounts!
    DO NOT SIGN UP USING hotmail, outlook, gmx, sbcglobal, att, bellsouth or email.com. They delete our forum signup emails.

    A note to old forum members...
    I receive numerous requests from people who can no longer log in because their accounts were deleted. As mentioned in the forum FAQ, user accounts are deleted if you haven't logged in for the past 6 months. If you can't log in, then create a new forum account. If you don't get an error message, then check your email account for an activation message. If you get a message stating that the email address is already in use, then your account still exists so follow the instructions in the forum FAQ for resetting your password.

    Have you forgotten your password or have a new email address? Then read the forum FAQ for details on how to reset it.

    Any email requests for "can't log in anymore" problems or "lost my password" problems will be deleted. Read the forum FAQ and follow the instructions there - that's what we have one for...

  • Returning Visitors

    If you are a returning visitor who never received your confirmation email, then odds are your email provider is blockinig emails from our server. The only thing that can be done to get around this is you will have to try creating another forum account using an email address from another domain.

    If you are a returning visitor to the forum and can't log in using your old forum name and password but used to be able to then chances are your account is deleted. Purges of the databases are done regularly. You will have to create a new forum account and you should be all set.

Petcock Question

R

ron bayless

Forum Mentor
Past Site Supporter
My 1980 Gs 1000 With 35,000 Miles On It Has Had A Problem For Awhile Now.after 15 Miles It Starts Acting Like It Is Getting No Gas.i Sit For A Moment, Then Start Off Again.i Have Already Had Many Answers Here About The Possible Venting Of The Gas Cap Problem. I Decided The Inline Conshaped Fuel Filter Might Be The Problem So Yesterday I Took It Off.now The Bike Wont Start,acts Like It Is Getting No Gas.i Used 1/4 Inch Od Tubing To Connect The Rubber Fuel Line To The Carbs To The One Coming From The Tank.what Goes Wrong With A Petcock That Night Cause This.i Am Going To Take It Off Tomorrow And Dissasemble It To See If Something Is Clogged.any Input Here Is Appreciated.
 
The first thing to do is find out if you have gas flowing through it or not.
disconnect the fuel and vacuum line from the petcock. Iinstall a short piece of tube to the fuel and vacuum nipple on the petcock. Put the fuel tube into a cup. With the petcock in the run position, suck on the vacuum tube. Gas should flow into the cup in a steady, full stream. If not, then its likely the screen inside the gas tank is clogged. You have to remove the petcock to clean that screen.

Earl

ron bayless said:
My 1980 Gs 1000 With 35,000 Miles On It Has Had A Problem For Awhile Now.after 15 Miles It Starts Acting Like It Is Getting No Gas.i Sit For A Moment, Then Start Off Again.i Have Already Had Many Answers Here About The Possible Venting Of The Gas Cap Problem. I Decided The Inline Conshaped Fuel Filter Might Be The Problem So Yesterday I Took It Off.now The Bike Wont Start,acts Like It Is Getting No Gas.i Used 1/4 Inch Od Tubing To Connect The Rubber Fuel Line To The Carbs To The One Coming From The Tank.what Goes Wrong With A Petcock That Night Cause This.i Am Going To Take It Off Tomorrow And Dissasemble It To See If Something Is Clogged.any Input Here Is Appreciated.
Click to expand...
 
Use 1/4" for the vacuum line. The fuel line needs larger 5/16 size
 
Thanks For The Dimensions.i Imagine The Diameter Makes All The Difference In Flow And Overall Performance.
 
Ron, If there is the slightest hint of gas coming from the vacuum line, the petcock diaphram is leaking, causing reduced fuel flow. If this is the case, you may also notice that the spark plug in whatever cylinder has the vacuum line attached at the intake is running black/rich.

Greg
 
ghwrenchit said:
Ron, If there is the slightest hint of gas coming from the vacuum line, the petcock diaphram is leaking, causing reduced fuel flow. If this is the case, you may also notice that the spark plug in whatever cylinder has the vacuum line attached at the intake is running black/rich.

Greg
Click to expand...

And you might wait till after this test to fire up that long awaited Opus X, or Macanudo. :shock:
 
jimcor said:
And you might wait till after this test to fire up that long awaited Opus X, or Macanudo. :shock:
Click to expand...

Yes, mouthwash may be in order :-& ... unless of course you already use List@rine. Just give the better half a kiss, she'll know you've been working on the bike! :-D

GH
 
you guys are helpful and funny.i guess i am prettu dumb.the petcock has a larger bore rubber tubing conncected to the fuel tank where the fuel gauge apparatus is.i guess this is the fuel line.on the other side ot the petcock is a smaller diameter 1/4 inch bore tubing that runs down anc conects to the larger bore tubing again in the center of the back of the 4 carb bank of carburetors.i took the petcock off the bike.i saw the spring and rubber diaphragm and saw nothing wrong and was going to try the mouth to the line trick.the smaller line was what i was going to suck on.anyhow, the little spring popped out of my hand and i could never find it so of course the gl is the only bike that does not have a repair kit at the dealer,andersens or old bike barn so now i am waiting for a whole new petcock for $84.25.replacing with a repair kit sure would have been easier and cheaper.i hope when i get the new petcock on it actually fixes the problem.i swear, i spend more time working on the bike than riding it.are they all this way?
 
ron bayless said:
i swear, i spend more time working on the bike than riding it.are they all this way?
Click to expand...

Careful Ron! You're starting to sound like a BSA owner. :shock: [-X
 
ron bayless said:
i swear, i spend more time working on the bike than riding it.are they all this way?
Click to expand...

Ron,
Its all part of the love... I often just take a day or two away from the bike when its giving me trouble. Getin' her fixed and that first ride again makes it all worth while. Back to your petcock, I wouldn't hesitate to go to the hardware and find some small/lightweight spring say 3/4" long to get you by.... needs to be light pressure though. As far as lines go, sounds like you have a fuel gauge.

Not sure if your setup is the same way, but my 750 has three lines.

1.) Fuel line to center of carbs to petcock... 3/8" or so. This is the main fuel supply.

2.) Vacuum line from #2 intake to petcock just above fuel line. This is the "mouth sucking line".

3.) Vent/drain line from fuel sending unit cover to below/behind swing arm. I think they did this incase the fuel sending unit happened to leak, not allowing fuel to drip on the hot motor.

Greg
 
ron bayless said:
the petcock has a larger bore rubber tubing conncected to the fuel tank where the fuel gauge apparatus is.i guess this is the fuel line.on the other side ot the petcock is a smaller diameter 1/4 inch bore tubing that runs down anc conects to the larger bore tubing again in the center of the back of the 4 carb bank of carburetors.
Click to expand...

:-s :shock: Your vent/drain line is connected to your petcock???
 
i figure i should be glad a bike runs as good as a gs does after all these years andthe enigines are so bulletproof.its the little things bolted to them that break down,but 26 years for a part to work is a testimonial in itself.
 
Your vent/drain line is connected to your petcock???
__________________
i have a short tubing,about 3 inches long,on one side of the petcock.it is about 5/16 in diameter.it seems the exact length to connect to a metal tubing coming from the tank itself and this is also where the mechanism that powers the fuel gauge.the other side, the right side, if you were standing on the left side of the bike, the petcock side,is aobut 1/4 inch in diameter and runs down to a bigger 5/16 rubber line that is connected to the middle of the bank of carburetors.does the short line go to nothing?if so why is the metal tubing from the tank itself there?
 
ron bayless said:
.does the short line go to nothing?if so why is the metal tubing from the tank itself there?
Click to expand...


Someone with your model bike needs to chime in here as I don't understand your setup. The hose coming out the fuel gauge sending unit should be rubber (not metal) and run to underside of bike where if any overflow occurs it drips on the ground not on your engine. I don't believe there should be anything attached to this hose.
 
ron bayless said:
Your vent/drain line is connected to your petcock???
__________________
i have a short tubing,about 3 inches long,on one side of the petcock.it is about 5/16 in diameter.it seems the exact length to connect to a metal tubing coming from the tank itself and this is also where the mechanism that powers the fuel gauge.the other side, the right side, if you were standing on the left side of the bike, the petcock side,is aobut 1/4 inch in diameter and runs down to a bigger 5/16 rubber line that is connected to the middle of the bank of carburetors.does the short line go to nothing?if so why is the metal tubing from the tank itself there?
Click to expand...

With a vacuum style petcock (which will have two metal tubes coming out of it for attachment of hoses) and a fuel gauge, here's what you should have:

The two petcock connections (on the lower left side of the bike with the tank installed): one thicker fuel supply line connected to the carbs, and one thinner vacuum line which connects to a metal tube down by the number 2 carb (counting from the left side of the bike).

On the bottom of the right side of the tank (with the tank installed), in towards the frame, is the fuel-gauge sending unit. It has a half-round "cup" on the side of the tank, to collect fuel if its gasket were to fail (so no dumping gas on the engine and making a fire). There is a normally empty vent line that feeds from the bottom of the half-round cup down to where the centerstand is (your battery vent hose also goes down this way if you don't have a sealed battery).

[If you connect the hose from the fuel gauge sending unit to the petcock, then there is no vacuum to open the petcock, and your bike will run only on "PRI" (prime), and not on "RUN" (or "ON") or "RES" (reserve).]
 
yeeha! I dont know if this information wil solve the problem, but thelast post here from kalessin seems to contain all the answers given here in one statement.this is the best forum.every time my bike is not runing it is always from some simple screw up on my part.Like the time i stripped one of the studs on the oil filter cover,like the time i forgot which wire conected to what when i took the rear fender off to paint it,etc,etc.I need someone to followme around and smack my hands when i am about to do something to my bike.I love the old thing,gives me a rush when i crack the throttle open.Old hot rodder at heart, and i am 56 years old.You never outgrow your need for speed!
 
ron bayless said:
yeeha!,gives me a rush when i crack the throttle open.
Click to expand...

Ron,

Now don't start messing with the brakes on us OK?!:-D :-D :-D

Just kidding of course... I think we all learn something new along the way with everything, It's all part of the DO IT YOURSELF world, so don't trade in your skills.

Greg
 
U Got It Wrenchit! I Replaced My Front Brake Pads On My L Model And Soon Afterwards I Heard Metal To Metal Noises.i Thought How Can Those Pads Be Worn Out Already.i Had Turned One Of Them Wrong Side Out.made Som Grooves In My Rotor A Little Bit.i Admit It,working On Cars I Can Do,bikes I Am Dangerous.
 
ron bayless said:
U Got It Wrenchit! I Replaced My Front Brake Pads On My L Model And Soon Afterwards I Heard Metal To Metal Noises.i Thought How Can Those Pads Be Worn Out Already.i Had Turned One Of Them Wrong Side Out.made Som Grooves In My Rotor A Little Bit.i Admit It,working On Cars I Can Do,bikes I Am Dangerous.
Click to expand...

:shock: :shock: :shock:
 
You must log in or register to reply here.
Back
Top