I recently found a Motobecane 50v in the trash. My guess is it's either a 79 or an 80. Just got it running really well. Starts no problem, accellerates fine, reaches its top speed, however it does not idle. I thought this was because it was missing the idle screw, but i just bought an idle screw for a motobecane and it's still not idling. The Carb is spotless, I cleaned it today still won't idle. Now it is missing the back half of the exhaust. The exhaust also wobbles around, but i did tighten it up. It still wobbles. Could this be my problem? It sounds crazy to me. This is my first motobecane, i'm not familiar with their common problems. Any help would be great.