I am supprised no one has meantioned using a tool called a colortune its a glass spark plug so you can see in the cylinder and check to see if your running too rich or too lean
http://www.gadgetjq.com/ctune.htm
you can check it out here ^

 

Just got mine and its perfect for getting anything tuned perfectly, explains how to tune and trubble shoot running problems also

 

THis thing is very interesting. I like the fact can you rev the engine with it throughout the carb stages..... Nice! what MM is our spark plug?

 

neat - wonder if it would be better to have one for each cylinder to color match them all at the same time.

 

Yes you can run this spark plug in there but not too long they say about 5 minutes, with no load i would suggest getting the 10mm colortune because i didnt seal the adapter to mine and got it stuck in my cylinder head. and the engine will probally run better with just the 10mm colortune. but it works you can see whats goin on durring everything. one pice of mind is that i tried the one i got on a small engine and my ear can tune it better than the colortune, i yet to have to try it in the bike, hopefully it will work better, i think it will help in tuning the transition states in the carburetor better than my ear cause then you'll know what really is going on.

 

Lol I had one of them about 25 years ago for my car