If it was me I would clean the carb and rebuild it if necessary before I did anything else. And, it is pretty simple to pull the muffler and look at the piston.
Hey there Big Chief in Squamish,Im in Peachland 250,767 3168
you can call me if you get stuck or have questions , theyre great guys on this site
and the ( jabs are just fun ,not intended for insult ,Ive had my fair share too
The Yankee,vs Canadian ones get good laughs too ......Keith AKA president