These bikes are pretty awesome.
Soo did the previous owner run it with out up-jetting. If so I would inspect the cylinder and get new gaskets.
If it has the stock air box throw it away.
https://www.mopedarmy.com/forums/read.php?7,4294534
Here is how to derestrict the stock exhaust.
I would check for air leaks. Get a temp gauge, upjet it till till it four strokes then go down one jet size.
Look up how to tune the clutch.
It is a nice bike. Take the time to get it right and it will run for years.