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Main Area => General GS500 Discussion => Topic started by: jiggersplat on April 15, 2004, 08:11:01 PM

Title: fuel delivery... runs on prime only
Post by: jiggersplat on April 15, 2004, 08:11:01 PM
i already replaced the vaccuum hose to the petcock, so i'm pretty sure it's okay.  i *think* it was working before i took the bike apart in the fall, but i can't be sure since the petcock plate was rotated around so i'm not sure what i was running on before and i don't know if the hoses were hooked up correctly when i bought the bike.  does this sound like what typically happens when the petcocks fail or is it something else?

thanks,
dan
Title: fuel delivery... runs on prime only
Post by: 500rider on April 16, 2004, 07:15:09 PM
I think there were some pics from the manual posted in the forum not too long ago.  This might help you make sure you got the hoses hooked up right.  

Rob
Title: fuel delivery... runs on prime only
Post by: ladybrid on April 19, 2004, 01:57:13 PM
I was having the same problem after last fall's work, finally got to trouble shoot and figured out that the fuel shut off at the tank was getting turned off.  :oops:  My logic was that it was on one way/off the other way, when really the on is in between.  :roll:
Title: fuel delivery... runs on prime only
Post by: jiggersplat on April 19, 2004, 07:09:13 PM
sorry... maybe my post wasn't clear.  the bike *does* run, and i know the hoses are hooked up correctly now.  the problem is i get no fuel with the petcock on ON or RES.  only PRI works.  i'm pretty sure the vaccuum line is good.
Title: fuel delivery... runs on prime only
Post by: ladybrid on April 19, 2004, 09:40:15 PM
No, you're post was clear, I had exactly the same problem, could only get it to run on Prime.  tried replacing the petcock, checked all the lines, made sure everything was not in backwards, noticed that the on/off at the tank didn't do what I expected at the setting I expected, and somehow by taking it apart and putting it back together enough times, it "fixed itself".
Title: fuel delivery... runs on prime only
Post by: newbieone on April 19, 2004, 10:14:04 PM
Try draining all the fuel from the carb. bowls, once that is done. Place the petcock, on "ON" wait a moment, and drain the bowls again, that way you should be able to determine if you have the two switched, bc prime should only put a little fuel in there, and if the petcock only drains a little on "Pri" then i'd say that there are backwards, bc you have to have it running to pull a vacuum. You get the drift here. good luck, by the way, what does it do on "RES"?
Title: fuel delivery... runs on prime only
Post by: jiggersplat on April 20, 2004, 05:23:43 AM
how would i be getting any fuel at all, even on prime, if it was the shutoff valve at the tank?
Title: fuel delivery... runs on prime only
Post by: newbieone on April 20, 2004, 07:07:08 AM
I'm not sure about the petcock at the tank, seems to me that it is working fine. One of these other guys posted up a more detailed suggestion recently, do a search for it, and you will probably come across it. Or maybe they'll be sweet and post it here for you.
Title: fuel delivery... runs on prime only
Post by: Kerry on April 20, 2004, 09:19:53 AM
Quote from: newbieone[...] you should be able to determine if you have the two switched, bc prime should only put a little fuel in there, and if the petcock only drains a little on "Pri" then i'd say that there are backwards [...]
Huh?

The PRI setting does not have its own fuel line.  The two hoses from the tank are labeled ON and RES.  I think that the PRI setting uses fuel only from the RES line, but I don't know this for sure.

Using the PRI setting to determine whether the hoses are switched will only work if the fuel level in the tank is below the ON outlet but still above the RES outlet, and ONLY if the PRI setting pulls from only ONE of the hoses.  (Still an unknown.)

I'm not sure what you mean by "prime should only put a little fuel in there".  But I know from multiple personal experiences that the PRI setting will totally drain your tank.  (OK, down to the last tenth of a gallon or two.)  I have used this handy fact to get to a gas station after the bike has "run out of fuel" on the RES setting.

===========================

Quote from: jiggersplat[...] the hoses are hooked up correctly now. the problem is i get no fuel with the petcock on ON or RES. only PRI works. i'm pretty sure the vaccuum line is good.
Assuming that the vacuum line (and its connections) are good, I can only think of two possibilities:

1) You have very little fuel in your tank.  (You haven't mentioned yet how full it is.)  As I said above, the PRI setting will let fuel flow even after the level in the fuel tank is too low for the RES line to work.

2) The diaphragm in your ON/RES/PRI petcock is faulty.  I haven't had mine apart yet, but others have found rust (or other junk) in there, or possibly a hole? in the diaphragm.
Title: fuel delivery... runs on prime only
Post by: jiggersplat on April 20, 2004, 10:26:45 AM
PRI will run your tank completely dry (i found this out the hard way), so yeah, it's hooked up to the reserve line.  there's plenty of gas.  i guess i'll pop the petcock open when i get some time.

thanks,
dan
Title: fuel delivery... runs on prime only
Post by: newbieone on April 20, 2004, 10:34:29 AM
Well thanks for setting me straight here Kerry.  I need to read the manual a little better, but I just thought I had a logical bench test for testing the petcock only I guess. anyways, your way sounds better. thanks

good luck getting it fixed.
Title: fuel delivery... runs on prime only
Post by: Kerry on April 20, 2004, 10:51:11 AM
Quote from: jiggersplatPRI will run your tank completely dry (i found this out the hard way), so yeah, it's hooked up to the reserve line.
My hesitation was about whether the PRI setting pulls from only the RES line, or if it has access to the ON line as well.  I'm just not familiar with the "innards".