bought 15 40 part sythetic high milage oil

[oldkid]

I changed my bike into full synthetic at about 500 miles. I took the Chinese oil out very early, about 25 miles l think (looked for metal filings and cleaned the screen) and then ran USA dino oil till about 300 to 400 miles during breakin. After that it's been full synthetic. I woud not worry about the high mileage label. It's usually just additional stuff to keep the gaskets and seals better.
I had a Jeep Cherokee that leaked a few drops of oil, and changing to the Castrol GPX synthetic blend high mileage stopped the small leak.