Motorcycle Repair: motorcycle not running properly, sparkplug, shively

Question
Well..I have a 1985 (roughly)Kawasaki dirtbike...maybe 75cc..2 stroke...When i first replaced the sparkplug with a new one...it ran fine my after maybe 30 minutes of riding i heard a popping sound...like it was missing...so I shut the bike off and i couldn't get it started again..i took the sparkplug out and noticed that it was way to oily...so I was wondering if this may be from to rich of fuel? If this is the problem how would i be able to fix this?

Answer
Hi Sean,

I think you're on the right approach with diagnosis. I would need to perform a few checks to accurately diagnose the cause(s) of the problem(s).

I suspect the fuel/oil ratio is off or the carburetor needs cleaned/tuned.

If the fuel is premixed, discard the current fuel and mix a fresh batch. Inspect/clean the air filter. Clean the spark plug and then try starting the engine.

Respectfully,
Mark Shively