Unfortunately there is no strainer on the petcock. Just a brass tube, and a second hole for the reserve. Knowing that there should be, I will see about sourcing one, and getting it on there.
If you want to check fuel flow to the carb, all you have to do is take the hose off at the carburettor and turn on the petcock. That should tell if the filter is a problem.
I had a shovelhead that would barely run with an inline filter. took it back off and run the gas line straight through,bike ran great. Find the proper in-tank screen and try it!