Yes,,, synthetic oil is not what id use for break in,,, they say that the piston rings won't seat properly,,, seen this many times at the race tracks and in the heavy haul engines...
Good old non syn oil for my engines,,, $3 bucks of oil to run the motor to 360 hours of life time,,, then bolt in a new replacement engine when the times comes...
At $240 for the """whole kit""" shipped to my door it aint worth thinking about rebuilding... Ha...
That would be about $140 ish in Usd funds...
We can get a new engine only at $60 bucks,,, $30 ish Usd... Engine,,, carb,,, out put sproket...
Oh yha