I hope the members here can solve this problem.
I have 2- 1976 Motobecane Cady mopeds. Both actual 378 miles since new. Got them and cleaned out the carbs, gas tanks, sparks etc. All the normal things. One started and purrs beautifully. This is good as we can diagnose for one to the other. The other had no spark.
1. On the no spark moped we found the timing was severely out of timing.
2. I replaced the condenser and points. With the timing set properly we now have great spark.
3. If I put gas directly into the cylinder we great some spark and the engine runs only on that gas. Thinking it was the carburetor, I placed the carb in question onto the moped which runs and it fires up easily. So I ruled out the carb.
4. Next thinking it was gas flow I hooked an external gas tank and line directly to the carb. Gas flows but again the engine won't fire.
5. I have made sure the seals on the exhaust area are tight thinking a air leakage problem. Didn't help.
6. I must be missing something simple as we have spark, gas and air. Should I disconnect the choke cable? When I move the throttle you can feel the movement at the carb.
I would really like to solve this mystery. Any and all help is appreciated.