I was running a standard fuel pump back then dude, and 4 bar at 394cc seemed to be abit much for it.
But now I've got an updated fuel pump in there and gone back to a 4 bar regulator.
Keep meaning to do update but just haven't had time.
It didn't run the best with out a map, the idle was very lumpy and would hunt. Plus I never went over 3,500rpm with out it mapped just in case it leaned out to much.
So yes it would drive, but not very well, and I didn't go high rpm.