fuel flow question

Been having trouble with the carburetor, I decide to take it to the local shop to someone
who could get me back on track. The guy I think did a good and the bike run better then every.
But I do not have the a vacuum line connected the petcock and never have. Will that make any diffence.
Now the bike run about 4 miles and run out of gas. I see no fuel in the clear filter then after a while
we go again for 4 miles. I alway put the lever on pri just a habit. Why is the fuel not flowing, the petcock is not restricted.

Thank you 650ed and martin csr
I was trying to be over cautious and purchase a better fuel filter. I guess bigger isnt always better,found it
Thanks agains guys.

Are you in Arizona or Azerbaijan? What year & model is it? The fuel flow problem could be a clogged tank vent.
Since it has PRI, I'll assume the fuel valve is a vacuum petcock & it should normally have a vacuum line connected to it.

ON & RES --- fuel only flows when the engine is running --- engine vacuum actuates a spring loaded diaphragm, allowing the flow of fuel by gravity --- when the engine is stopped, the spring returns the diaphragm to the closed/off position.

PRI --- bypasses the diaphragm assy -->> fuel flows by gravity -->> engine stopped or engine running.
Use PRI to prime the carburetors. If left in PRI while the bike is parked, fuel may leak out the carb overflow tubing.

Use ON during normal riding. Switch to RES when the fuel gets low & the bike starts sputtering from lack of fuel.

RES = reserve --- uses up the remaining 1/2 gallon or so of fuel in the tank. You can go 10-20 miles on RES, so refuel asap.

If you have a vacuum operated petcock you need a line connected from it to the vacuum port on the #2 carb. Otherwise, the petcock will not operate properly and you will keep running out of fuel unless you place the petcock in the PRI position. Ed

does it matter which port on the carb connects to the petcock? all vac ports should do the same right?

You can use any inlet for the vacuum, but make sure any unused vac takes offs are plugged.

No flow on prime after 4 miles is likely a blocked fuel tap strainer -inside the tank.