Does anyone work on 1980 650xs near missouri. I am at my wits end and dont have the knowledge to figure out the issue. 1980 650 special. It will start but when you give it throttle is stutters and backfires. It has auto timing. We replaced the stator, rectifier, cleaned and replaced the jets in the carb and no change. Sometimes it runs at 70% but if you turn it off it goes back to run like crap.