summit carburetor
I don't think there was anything particularly wrong with the design.
1) The accel pump shooters are part of the boosters, the only way to enlarge the shooters is to drill them out. Go to far and you have to replace the booster assembly.
2) Wicked lean spots with accel pump- I ended up drilling the shooters AND modifying a 50 cc pump off a double pumper to get working. And this was with a vac secondary carb.
3) very pooor transitions between circuits- I have an O2 gauge and vacuum gauges in the GTX and you could see when moving from one circuit to another while driving (idle/part throttle/power valve actuation/etc) the carb either like to dive off scale or run full rich, no in between.
4) No gaskets in fuel is b.s. the power valve housing up front use to puke fuel all the time.
5) The base where the intake gasket sets is hollow, not a lot of meat there.
Maybe Summit fixed this issues, one would hope so.