give it a shot of starter fluid to see if it fires.... that will tell you for sure you have a fuel issue
you need to CLEAN everything, like tweaker clean it. all those little passages get even a little varnish in them and it runs like shit.
torch tip cleaners, or new jets. carb dip the carb bodies, new crossover tube, blow everything out with full pressure compressed air
not that 30 psi reduced safety shit.
remove the petcock and clean/replace the screen, then reinstall with new gasket and turn fuel on through fuel line and verify
you have good fuel flow through the T fitting to each carb.