petcock problem

[garyheskett All 49 x 3 st.louis]

Last May, I had "petcock failure" while in Colorado on a late Saturday afternoon.  The spring was reversed, vacuum line plugged, and the petcock now must be turned off manually. Everything works fine since then till a month or two ago.  I usually run out of gas at 132 miles, switch to reserve and get 4.0 or 4.2 gal of gas.  Several times lately, I haven't switched to reserve (145+ miles) and will stop for gas and get 4.7, 4.8 gallons.  I sure ain't a mechanic, but unless the long tube on the petcock broke, how can I be getting that much gas when I haven't switched to reserve yet. I did run out completely one time thinking I had 30 miles on the reserve and only went less than 10 miles. The petcock works in the off position, because I forgot to turn it on once (ok, 5-10 times)(ok, more than 10) when I turn the key on and head out and the bike runs out in 1-2 miles. Before I take that tank off and petcock out again, I thought I'd ask what you guys thought.  Thnaks, Gary

[olddog1946]

I don't believe you have the knob clocked on the petcock properly.  Remove the screw and the bolt for the control knob, pull it loose and set the petcock to off, then reset the knob to off and re-install. It is also possible that plastic knob is split or broken and not actually turning the petcock.

[Blackduck]

Check that the selector knob is not binding on the Chrome mounting
If it is it will hold the petcock ball of it's seat.
You have to align the petcock  or open up the hole in  the Chrome piece.
Cheers Steve

[garyheskett All 49 x 3 st.louis]

Thanks for the responses, but,,, the petcock has worked "normally".  There have been times I ran out and switched it to reserve and it worked as it should.  But lately it won't "run out" at the normal mileage and when in the "on" position I will get 4.8 or 4.9 gallons. Since I've taken the petcock off numerous times, I can't think why I could get so much gas unless the "long tube" from the petcock possibly broke. But like i said before, I sure ain't a mechanic. Any thoughts?

[alph]

i don't understand how the spring could be put in backwards?  when i looked at mine i thought about reading someone else's post saying the same thing, so i looked over the spring several times, and both ends are identical.  not only that but the spring pushes against a plastic plate that has the diaphram attatched on one side, and a check valve that releases the vacuum on the other.  it's actually a simple system. 

good luck, keep us informed on what you find out.

[Blackduck]

By backwards he means putting the spring on the inside to hold the petcock open.
A good trick if on the road and the vacuum diaphragm craps out, just turns the petcock into a manual system.
Cheers Steve

[Bone]

Sounds like the reserve isn't sealing. Your running on reserve the entire tank. The ball in the petcock doesn't stop correctly or crud in the seat is not allowing the ball to seal the opening.




I= Fuel inlet from top of stand pipe.
J= when ball is over this hole, Valve is in ON position.  ( reserve fuel inlet closed)
K= when ball is over this hole, Valve is in RESERVE position.  (both on and reserve fuel inlets are open)
L= when ball is over this hole, Valve is in OFF position.  (this is fuel outlet from manual side of valve)

[Ricky-D]

Sounds like the reserve isn't sealing. Your running on reserve the entire tank.

This is the problem I would think.

It has also been the case where improperly connecting the knob has had this same effect as has been previously mentioned in some postings.

For this same problem I have gone with a Pingle.

Nothing as nice as having full confidence in a system.

***

[rmrc51]

Same here regarding the Pingle.

I was beginning to have issues with my stock petcock. Tried rebuilding it twice and finally raised the white flag and went with the Pingle. No problem since then.