The thumbscews are mixture screws with a large serrated head
so you can reach in adjust them by hand without needing a screwdriver.
As for the jets,like I said my airbox is
about as open as you can make it and the
TBS needles and 130 jets flow enough fuel.
My plugs run a nice clean tan and I don't
have any flat spots through the RPM range
and I run a 17 tooth front sprocket to help
wind it up.
