1979 SF Fuel out of the petcock diaphram air hole

[yesiamspecial]

I have a 1979 SF that is spitting fuel out of the petcock diaphram air hole. I believe this is the air hole that returns air. I noticed it while I was riding and when I checked the diaphram there are no holes or tears.

Anybody have any idea what's causing this? is it a bad petcock? or should I rebuild the petcocks and the diaphram or is it something altogether different?

Thanks,

-Jacob

[Ken Talbot]

Hmm, this is a bit of a mystery. Specials have a diaphragm in the octopus, not in the petcocks. The petcocks have only a rubber gasket with holes to direct the flow of fuel according to the position of the lever. Are you sure you have a Special?

[bikerphil]

leak

If you do have the octopus setup (special), Now would be a good time to eliminate it and add some in line fuel filters. JMHO.

[yesiamspecial]

octy

yeah, sorry, what i meant by petcock diaphram was the octopus diaphram. All lines running to it from the two petcocks. Replacement with in line filters sounds like an easy enough job. Any tech tips or posts you could point me to?

Thanks,

-Jacob

[bikerphil]

fuel line routing

1. Remove octy and all fuel lines + vac line to #2 carb boot.
2. Cap off left front and right front petcock outlets (prime position).
3. Run fuel line from left rear petcock outlet to small in-line filter, then down to RIGHT carb fuel inlet.
4. Run fuel line from right rear petcock outlet to small in-line filter, then down to LEFT carb fuel inlet.
5. Cap off vacuum port on the #2 carb boot.

Also: Don't forget to turn both petcocks to "off" position after done riding. HTH

[yesiamspecial]

rebuild the octopus

The inline replacement is definitely easy but I don't like the idea of constantly having to shut off my fuel every time I switch off the engine. Thanks for the tip, though. I'll probably just rebuild the octopus. The dealer sells it new for $180 complete or my local shop sells the rebuild kit for $40. Still, I'm confused why it spits fuel out the air hole.

thanks,

-Jacob

[DiverRay]

Jacob,
It spits fuel out the air hole because there is a hole in the diaphram. You MAY not be able to see it, but it IS there.

[yesiamspecial]

diaphram hole

Kewl. So the hole in the diaphram that lines up with the hole in the spacer (plastic piece) is bad? Good to know. I know there are four holes in the corners for the pegs that hold it in place when the octy is all put together. Or there may be another hole I just didn't see.

This whole thing started after I went out of town for a week and it just sat in my driveway.

I was curious if something came loose or what. Still, it's 30 years old so not surprising when the little things wear out.

Thanks,

-jacob

[bikerphil]

octy

Read this thread...

http://xs11.com/forum/showthread.php?s=&threadid=4425&highlight=octopus+rebuild+kit

[thewiz]

"started after I went out of town for a week and it just sat .."

Sounds like your bike has possibly caught a dose of latexosisitis caused by a rubber eating bacteria latexococus. Been recently found in southern ID ... maybe came down the Interstate on a zephyr.

Cure is simple ... rebuilt the Octerpus or get rid of it altogether. Then one half can of Seafoam in a full tank and RIDE

[yesiamspecial]

dang latexococus

shoot. that explains why my 30 year old bike needs all the rubber replaced! LOL! Yeah, time for a rebuild. all my local shops are sold out of the special but I found one on oldbikebarn.com