What happened? Petcock question

[mm1ut1]

Recently started working again on my 1100. I put the carbs in after hooking them up to a gas tank to see if they would leak. I had replaced a bad gasket and cleaned a float valve . Everything looked good so I installed the carbs and hooked up a temporary fuel line. No octopus, just a direct line to carbs with a petcock connection line and filter. I did not connect anything to the prime fitting on the petcock. Turned both petcocks to on, waited a few seconds to check for leaks then hit the starter. Engine fired right up and everything looked good. After about thirty seconds I shut the engine off and turned both petcocks to Off. Gas then flowed from both prime connections on the petcocks . Probably a couple ounces, maybe more. I have no idea why this happened. I have run gas out of the On line with the tank off and never had a problem. Currently tank is off the bike , petcocks turnd off , no leaking.

[Socer4m]

Maybe I missed something but the two outlets on the petcock,,,,one is for a vacuum line and the other is for the carb hookup,,,,there is no prime only outlet. The vac outlet goes to the missing octopus and the other goes to the carbs. ?? I had the dreaded octopus years back on an xj1100 and got rid of it and cannot remember if the petcock was different than all the other xs1100's,,,,can someone else chime in on the two petcock outlets???.......Mike in S.Diego and Pa.

[bikerphil]

The front outlet on both petcocks is prime and should be capped off. Hook your fuel lines to the rear outlet.

Make sure the left side selector has an "L" stamped in the center, otherwise someone may have mixed up the left and right parts during a rebuild.

[DiverRay]

+1 on Phils post. You nees to verify that the parts did not get changed between Left and Right! I've capped my prime and run with no Octy on my '79 Special. Only problem I've had is too long fuel hose causing kinks.

[Hawkinspickle]

+1 on Phils post. You nees to verify that the parts did not get changed between Left and Right! I've capped my prime and run with no Octy on my '79 Special. Only problem I've had is too long fuel hose causing kinks.

To avoid kinks, I routed the lines cross-cross, i.e., Left petcock to right carb set and visa versa. No problems and the lines lay nicely over the air box rubber joints. Another benefit with this cross-cross is that you can lift the back of the tank up and then easily connect and disconnect fuel lines from the petcocks.

[Ranger_xs1100]

On the xs11 models that use the octopus, Both of the fuel taps on the petcocks are gravity fed fuel outlets. The vacuum line goes to the octo only, not to the petcocks. I don’t think that it is unusual for one or both of the fuel taps to have some fuel flow while turning the on/off/res/prime lever. However, there should not be any flow or fuel leakage from either fuel outlet tap in the off position. As stated above, you can cap off the front fuel tap which is used for prime to bypass the octy becuase It is not needed when the octy has been removed. Or you can run both taps into a tee or y connector and then directly to the carbs.