equalizing air flow???

hey guys can someone tell me how to equalize the air flow on theze carbs? the bike seems to run great at higher rpms,but on lower rpms i get a miss and poor performance. i checked for leaks around the intakes and carbs ,but got nothing,,,,,oh and on off idle ecceleration i get a guess what you would call a backfire sounds like a cough....lol any help would be greatly appreciated thanx

If the bike has been sitting for a few weeks, there could be trash in the pilot jets. Could also be crud from the tank. Is there a filter in place? Synchronizing the carbs is not real complicated and there are several threads and tutorials on this site. The search function will find them.
There may also be a link to a pdf of the factory shop manual, which I assume you do not have. Copies of them are often for sale on eBay. It is well worth the price.

PS Which bike and carbs do you have?