Best port for petcock - '77 650B1

Folks,

I've had to replace the stock manual petcock with a vacuum one. I just checked my carbs and they don't have the port for the petcock.

Can I just run a line from one of the sync ports?

Thanks!

Yes, that should work. It shouldn't matter which carb you chose because assuming the carbs are sync'ed all 4 vacuum ports will be pulling the same level of vacuum. Ed

Cool, Thanks, I figured it'd be fine but I thought I'd double check.

I would tie all four together-you need full vacuum to operate the petcock-Good Luck

The stock setup is one vacuum port for the petcock.... one is all you need.
A typical problem w the vacuum petcocks is diaphragm failure or a diaphragm o-ring that needs replacing or doesn't seat properly.