Just inherited a KLF300c that hasn't been run in a pretty long time. Before starting we cleaned the carb, changed the oil and gas. It starts right up and idles perfectly but when you open throttle it backfires through the carb. If I run it on half choke I can get the revs up somewhat but then it will start backfiring again. It appears to me that it's running too lean but I can't understand why that would cause it to backfire through the carb. I have done my utmost to make sure the carb is as clean as I can get it. Any suggestions or help would be greatly appreciated.