Motorcycle Repair: 81 SECA, where does petcock vacuum line connect, vacuum hoses, vacuum ports

Question
Hi,
I recently scorde a 1981 SECA 750 for $350. Part of the good deal I got was that it didn't run. Took the carbs off and cleaned them. Am reassembling now. I got this vacuum line coming off the petcock and know it must hook to a vacuum port somewhere. Have tried laying out the line and seeing where it ends and looking there. Do you know where this line connects to. I got a Haynes manual, but it is next to useless.
Thanks mucho,

Stan Davis

Answer
Hi Stan,

The vacuum hose connects with the #2 carburetor intake manifold. Cylinders and carbs are numbered from left to right: 1-2-3-4, when seated on the motorcycle.

The intake manifolds vacuum ports should have rubber plugs on ones not used for vacuum hoses.

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Respectfully,
Mark Shively