Motorcycle Repair: 1984 nighthawk, air fuel ratio, realistic limit

Question
Hello  Bill, thanks for your quick and helpful response last question, and now i have another. In reference to 1984 nighthawk 750 S, i asked about  lifting the  needle to  richen the mixture, to compensate  for  alcohol fuel. The article I mentioned   suggested  2  washers, of  indeterminate   size. i assume they are  all stamped  from the  same basic material I presently  have  1  in the carbs which measures 6 /10 ths of  a millimetere
i figure  that the subject in the article had   twice that amount.
what is the realistic limit for this procedure ? consequences  of going over ? same  article mentioned   pulling the  "cones" out of the  end of the exhaust pipes and  drilling   3 or 4   small holes  along its length. Is this  worthwhile? I assume   a  slight increase in noise. my bike has  a k/n filter in the box.
same  website mentioned   drilling the bottom of the air box, but that seems risky if caught out in the rain.. Thanks for your help, Frank

Answer
Frank, it all becomes trial and error, unless you have a dyno with air/fuel ratio equipment.

The more you change the intake and exhaust systems away from stock, the more carburetor fiddling you will be doing.

Honda spent a lot of time getting the jetting right, but having to compensate for EPA regulations.
You have to read the plugs, feel the way the engine is reacting to changes and monitoring fuel mileage.

I'm not a fan of loud motorcycles, so will not encourage drilling and component removal for some kind of "perceived" increase in performance, which usually just means that it is louder not faster or more efficient.

Bill Silver