main jet will only be useful at wide open throttle. If you knock I suggest you modify the needle position in the carb. there should be notches on the needle, I suggest you move the needle upward one or two notches.
The needle shift will enrich the whole curve, specially with partialized throttle.
Then if it's still not sufficient, you move forward with a bigger jet...
The needle shift will enrich the whole curve, specially with partialized throttle.
Then if it's still not sufficient, you move forward with a bigger jet...