Could the petcock diaphram be the culprit

[nicknovice]

My bike always runs. But seems starved for fuel after a while. Of course I tried opening the fuel cap to no avail. I disassembled the petcock and found the diaphragm stuck closed? Could this be my issue? I rode it around goon style, while holding my auxiliary tank, and it ran fine. The manifold vent was a dangling participle. Why does it need that vacuum to run? I know my carbs need to be synched. But if I put my thumb over the tube at idle, it dies. Is that normal? This bike has kicked my ass since I bought it.

 

[drewpy]

I would say the pet cock needs a rebuild or at least a strip and clean.

is the vacuum pipe connected to to petcock during normal use?

its needed to pull that diapram open to let the fuel flow!

 

[nicknovice]

Yes, it's normally connected. But does it need to only vac a seal, or does it vac continuous air? Should it die when I stick my thumb over the tubing?

 

[drewpy]

vacs continuous to keep the diaphram open.

shouldn't die, that's why I said it may be too rich, or the tickover is set with it like that!

 

[nicknovice]

The jetting is a mess. Though I went with a recommendation on here. Open pipes, no airbox, filters... As soon as everything is sorted, it's going on the dyno. Lets hope is stays in one piece. I'm not looking for HPs (or I'd be silly).