Today while taking the carbs off to send away, I decided to finally test and see if the frame petcock was one of the issues at hand. So I disconnected the hose from the bottom T on the carb, set it into a cup and went through the motions of going from position to position on the carb. Bike was off, everything was essentially like it would be on a standing bike. With everything like it was, I noticed it was letting gas through while in the ON position, then when I switched the RES it went to a trickle and eventually stopped and in PRIME nothing happened.

Now I don't think this is what it is supposed to be like and in fact I thought it was supposed to be the opposite (nothing in ON and RES but free flow in PRIME). Anyone have ideas of what to do? Get a new petcock, maybe do something with this one?

And on a side note, does anyone know what the fuel hose sizes are for all of the hoses that carry fuel? I believe 1/4" or 5/16" will work from tank to petcock, but is it the same from the petcock to the carb? And what size are the other hoses from petcock to carb?

Total noob here but arent the petcocks vac actuated and actually require a vacuum signal to work correctly?

They should.  That's why he is concerned that it flowed in the ON and RES position.  It should only flow in the PRIME position if there is no vacuum.

As long as it is connected properly, I would say it's time for a new petcock.

If someone took it apart, they could have put the metal clip on backwards. Then ON=Prime and PRIME=ON.

Easy way to tell, just send us a pictures of the thing in what you are calling the ON or PRIME postion.  Then we will be able to tell.

Quote from: bombsquad83 on September 05, 2012, 01:11:56 PM
Easy way to tell, just send us a pictures of the thing in what you are calling the ON or PRIME postion.  Then we will be able to tell.

Large end of the lever facing up (direction of arrow) is what I refer to as ON, then rotating clockwise to go to RES and PRI.

Edit: If I'm in the market for a new petcock, should I go for the newer style? Should I just post a WTB?

Someone put the face of the thing back on wrong lol

PRI is at 12 o'clock, RES at 9 o'clock and ON at 6 o'clock when looking at it head on

New and old petcocks are not interchangeable. They mount different to the frame. Hose sizes on new ones are larger.
You probably could make a mount for it.

This may seem silly but maybe the shutoff under the tank is off.  It just seems like something I would do.

I don't know if this will help, but I have an 05 petcock (frame mount) that I filled down the stop tab on my plate cover which hold on my nob, which doing let's me turn my non 360 degrees allowing me to have a gravity fed on position at 9:00 and res position at 3:00. I completely cut out my vacuum on the petcock which doesn't let me funtcion my original on and res functions/ so I just use them as fuel off.

    I don't know what style petcock you have  but I know cleaning them can help out a lot. Also frame mounting. Newer petcock seems fairly easy considering it's only two mount holes to be drilled.
     
     Good luck with your fuel gremlin

2004 and newer GSs have a completely different petcock design. Watevaman, what you described as ON is in fact PRI, what you described as PRI is ON. It seems that your petcock is working properly. Problem solved!

Arrow pointing down is ON. Arrow pointing UP is Reserve. Arrow pointing back is prime.
2001+ Models


89-2000 models

 According to that second picture mine is correct then. The arrow on the long part confused me and I'm kind of confused as to why it's even there.

The arrow is there because it should point to the current setting...right?

 Not unless the labels are wrong. When the arrow (long side) is pointing down, like in that picture, my petcock says PRI at the bottom.

My '93 looks like that and down is on, same as that pic.

Here's the one from my '99. It's the same part as the '93's.



On the pic, the petcock is ON with the long end of the tap DOWN. If you look carefully for letters behind the tap, you can see a "P" near the 12 o'clock position. It says "ON" at 6 o'clock but the tap hides it.

If your petcock has the letters PRI in the 6 o'clock position, they should be upside down when the petcock is oriented like the one on the pic. If so, then someone's rebuilt it and installed the ring upside down.