A friend gave me an 81 cb650 4 yrs ago, It hadn´t been run for 20yrs, just parked and left standing protected from the weather. with minimal work and parts from ebay I got the bike running great. The guy who gave me the bike had a renewed interest in it, so i sold it to him for the cost of parts I put into it. Circumstances arose that he had to give it up, so he gave it back to me. During the few months he rode it, the rear swing axle bearing had to be replaced and he took it into a Honda dealer. The dealer also felt the tank should be relined, I had this done under my watch, The bike never did perform well after this service. It sat for a couple of yrs in my basement till I got around to looking at it. The carbs were plugged up with stabilizer and a creamy brown material. I cleaned the cards and tank, but the 2 right cyl didn´t seem to be functioning correctly, they didn´t get as warm as other 2. I pulled the carbs and went thru the cleaning procedure again, seemed all were firing good now, but maybe the acelerator pump was not working as I could not rev it up without using some choke. Off came the carbs again, just checked everything was clear, couldn´t see anything wrong. Now the right cyclinder isn´t firing. Lots of spark. Any ideas other than there might still be a carb problem. The bike has under 15kkm on it, hardly broken in. Tks Jack D