I found my 21 was really painfull down low as well. And hard to start. Hard to take off under 4-5k. I changed the air screws to 2 full turns out (they were 1.5 each before) and it made it much better. Easier to start as well.
I think it would actually be better with another 1/4 turn out but its come into winter over here so the cold air will help with that a little.

The carbs actually line up with the respective cylinder if you look at them from a riding position.
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