Yep could be either, but most likely the CDI or Mag coil if the plug looks pretty clean and your not getting any spark or just very weak orange spark.
Check to make sure you're actually getting fuel to the engine also.
Originally Posted by MadC
this thread is old, but it helped, sorry I didn't get back to you guys..
It actually wasn't a clutch problem, it's weird... I changed a broken metal seal between the head and engine. and the noise stopped.
But now the problem I have is new. I can't get the bike to go, the bicycle tries to start, sounds like it is trying to give it gas when throttle is turned, but it just won't start...
peddling my ass off with it running, having the gas go into it but not starting...
could that be a spark plug or CDI plug problem?