valve in prime position, but no fuel draining

[joviyach]

Hi all, I finally got around to getting my gas tank off today en route to getting the carbs off, but funny thing is that though I have a nearly full fuel tank (of 2+ year old gas) nothing came out. Is this an indicator that the valve may be bad? BTW... I found the vacuum leak. There was a hose coming from under the gas tank that was not attached to anything. I am guessing that it is suppose to go to a connection in between the two carbs on the right that had no hose connected to it.

[BassCliff]

Hi Mr. joviyach,

See the following for pictures and comments:

Where Do These Hoses Go?

On the bottom side of the tank, inside where it fits around the frame, there is a long hose that comes from the fuel gauge send unit and drains down behind the engine, past the battery box, to the ground in front of the rear wheel.

Yes, if your petcock does not drain anything when set to "PRIME" then I would get a new one. Have you looked at the filter screen on top of the petcock? Is the tank full of grunge and rust? I suppose the petcock could be clogged.


Thank you for your indulgence,

BassCliff

[psyguy]

the petcock lets quite a bit of fuel through in the prime position and if it's not letting any while the tank is full (i.e. under pressure) then something's seriously wrong.
take it apart and and have a look or better still, get a new one

[Nessism]

One exception to the above comments is the 1980 petcock without a slot which requires a quick vacuum pulse to open the prime (or so I've been told).

[rphillips]

He's right, with the "80" model petcocks, when on "PRI" you will need vacuum on the petcock to get the fuel flow started, after it starts it will keep flowing. Not just my opinion, I've been there.

[joviyach]

That explains it, but

unfortunately makes the leak...still a mystery. It would have been easier if those hose were actually supposed to be connected to something on both ends, now I am thinking the culprit must be the boots after all, which is what I originally assumed. I will probably just replace the petcock.