Topic: Gas leaking somewhere when petcock turned to "off"

[sinister902]

well, i went out today and smelled gas (just got the bike running two nights ago), and noticed a small damp spot under the bike. checked to make sure i didnt forget to turn the petcock valve to "off", and sure enough it was closed like i thought.....so, I figured i would post up to see what most commonly causes this to make sure i dont forget to check something.....

I figure it could be:

petcock internal seals/o-rings are probably shot
excess fuel bleeding from the carb bowls

is there any other possibilites with the vavle closed??

[Johnie]

Is the drip on the floor in the area of the center stand?  If so, it probably is a little weep from the overflow tube on the float bowl of the carb.

[sinister902]

yeah, the spot is pretty centrailized under the bike like you said. is there a way to prevent that from continuously occuring?

[Johnie]

Well, first you need to be sure your floats are set at the right height.  If you already did that then some guys just shut the fuel off like a mile from home.  By the time you get to your driveway the level will be below the overflows,  providing your fuel petcock is working.

[bryanj]

there are lots of posts on where the tap leaks

[sinister902]

Well, first you need to be sure your floats are set at the right height.  If you already did that then some guys just shut the fuel off like a mile from home.  By the time you get to your driveway the level will be below the overflows,  providing your fuel petcock is working.

how do i set the floats at the right height? i read through my clymer's but its for a 750(given to me for free) and my bike is a 550 so the carb section is a bit different and I can't compare the pictures very well.

[Bob Wessner]

Well, first you need to be sure your floats are set at the right height.  If you already did that then some guys just shut the fuel off like a mile from home.  By the time you get to your driveway the level will be below the overflows,  providing your fuel petcock is working.

how do i set the floats at the right height? i read through my clymer's but its for a 750(given to me for free) and my bike is a 550 so the carb section is a bit different and I can't compare the pictures very well.

Check here http://forums.sohc4.net/index.php?topic=17788.75 Scroll down to the 500/550 manual. You will see a series of PDF files you can download.

[Johnie]

Yup...Bob is right.  You need to get the right manual if you are going to be working on the bike.  We can give advise, but the manual has the pics.  You will be happy you got one.  Good luck with your bike.

[tx750]

My 73 CB750 would leak fuel only when on the side stand.When I took a closer look the float bowl gasket in #1 Carb was bad.When it was on the centerstand it would not leak ,just when it was leaned over on the side stand.

Good luck!