Hi im fairly new to the world of motocross and I am going to try and restore a 1979rm 100. My friend bought a new bike and gave me his old one. It ran fine until we blew a crank bearing. Not wanting to mess with the crank we bought a used engine off of **** and used the bottom end. Eversince replacing the bottom end we have had trouble with the engine. It will idle but once put in gear and ridden it will start to backfire violently, whole pipe shakes. Also after backfiring began we noticed the needle in the carb was bent, so we replaced with a new one and tried again. Unfortunately that needle also got bent. I really need help with this because my father wont let me buy a newer because he thinks they are to dangerous. He said if I could get this old one running i could keep it. So I really want to restore it. Thanks in advance for any replies.
