you had to richen further than factory settings? that is very strange. is the engine sounding crisp? or is it "4-stroking"?
biggest recommendation is to leave the mid speed needle at factory settings, as a basher you will not get enough gains to performance vs how much of a headache tuning it can be.
this is your engine correct?
https://www.cmldistribution.co.uk/di...MacStar_28.pdf