Motorcycle Repair: 1984 nighthawk 750 s, straight gas, bill silver

Question
Hello  used this  site before, and got useful info.
in canada , fuel contains up to 10 % alcohol. I found     a gas  station that sells  alky free, but cost more. on another  website, i read of   putting  thin washers in the bottom of the carb  slides to lift the needles slightly , and  richen the mixture. Is this  harmful in any manner ? I think the  bike could be richer,  It runs noticably  better on the straight gas, and im looking  for similar  results, richer  on the  alky/ gas mix.
Thanks, Frank

Answer
Frank, we are forced to use the same 10% stuff down here, too. A lot of the bikes carburetors were jetted lean from the factory to meet emission standards. Two things that are usually helpful are to disable the idle mixture limit caps, so you can adjust the idle mixtures more accurately and to raise the needles, ever so slightly, using a very thin washer.

For my latest bikes, a CB400F and CB77, both have reacted favorably to upsizing the main jets one size. The 400F went from #75 to #80 mains and the CB77 now has #140 mains instead of the standard stock #135s.

Richer is better, especially these days with alcohol injected fuels...

Bill Silver