42m Fresco or 48Mil Mikeck?

[JDale]

Running a stage 4 sx/jet 200 engine, 28mil dellorto with an original 80's underkick start 42mil fresco. Runs fine but seems to run out of puff at anything over 60'ish, I have a 48mil mk 6 Mikeck which I can try , would that be to big? would it allow the bike to better the on the top end, rev on a bit more.

I know sx gearing is not that great but I feel the bike has more to give

Thanks in advance

Rgds

JD

[RICSPEED]

i'd go with the mikec

[smiffy1968]

i'd go with the mikec

I agree, go with the Mikeck.