Your low needle is to rich and your high needle is to lean. Start over at 1-1/8 turn on the low and 2 turns on the high, adjust the high needle first for peak RPM then the low for the leanest transition possible. Correctly adjusted it will not accept throttle when cold, it will have to warm up for about 30-40 seconds first. It's impossible to get every bit of burble out of most gas engines but it should be able to be adjusted so it's clean from 1/4 to1/3 throttle on up.