Re: av10 head
Are you using the AV10 head which has the groove for the O-ring?
If yes, why are you running it without the O-ring?
Are you using the jet that came with your carb? I don't know about the clones, but real Dell'Ortos come with a 68 jet which is too large for a stock set-up.
Finally, why are you using an AV89 cylinder rather than AV7 on the 50V?