Motorcycle Repair: motorcycle not running properly, proper ratio, sparkplug

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,

If the fuel is pre-mix, empty the fuel and add a tank of fresh fuel/oil mixed at the proper ratio.

If the fuel is oil injected, inspect the carburetor for varnishing or other contamination that would block or restrict fuel flow through jets and passageways.

Inspect the oil injector for proper operation.

Inspect ignition system for proper operation.

After trying the above tasks, try starting the engine again.

Respectfully,
Mark Shively