the best thing i did on my bike to improve it was to put mikuni carb instead of the wearprone amals..oh i know what some guys around will shout but:
first the vm mikunis are older than concentrics so they are "period"
second ...they are much better makes and you wont pass your time to try to get a good clean carburation

nce set up they are forgotten..i spent ten years trying with amal...when new they are correct but it doesnt last ( have a look at the slides after 100 miles from new..they are scored like a 100 thousand miles mikuni slide...so try to have a decent tickover with an old amal (smile!)
third...when you ride your bike you can see the carbs and at meetings most people dont notice them..