Hello all. I've been browsing on here since I purchased an 81 cx500 with 33,000 miles. The bike has been taken care of for the most part but has had an issue with the left cylinder(when sitting on the bike) misfiring when revving or accelerating. Here's a list of things I have done to figure this out. I have drained the gas, added new with seafoam, checked and cleaned the K&N air filter, cleaned the fuel filter, changed out the vacuum petcock, checked for any vacuum leaks, changed out and gapped new NGK spark plugs, checked over the carbs and found no blockages or varnish, and switched the coils to see if it was a weak spark issue. I also took apart and cleaned the plug caps. The machine idles smooth and runs good as long as you dont tach it up. The tach cable is currently broken so I'm not sure at what RPM it's starting to "break up" at. If anyone has heard of this problem, I'd really appreciate any advice. My heads starting to hurt from scratching it...lol THANKS!