49.5cc JCL gas scooter will not start and SHUT OFF...

Question

I was driving when all of a sudden my scooter came to a complete stop and shut off when i was on a main road.  I pulled over and ever since, the pup wont start up.  Anyone have any ideas and if I can fix this myself instead of paying 90$ diagnostics and hrly rate to get it fixed???

I also have 1,200 miles on this and bought it only two months ago+   I recently changed the oil and gear oil and possibly put too much oil in.  I have no idea why this is not starting up.  SOMEONE PLEASE HELP!!!  Also i noticed on the left side on the rear tire there is a sticky residue dark color.  Other than that their are no obvious leaks or anything.  Please HELP ASAP!