Two stroke motors are like trumpets, keeping them playing at their best takes a lot of work and practice.
A two stroke adjusted to peak performance is only a hairs breadth away from a rebuild.
A two stroke never runs better than the minute before it dies.
My departed friend and mentor, who worked 20 years at Arctic Cat and a few at Bombardier taught me these axioms while we were rebuilding my 787 the first time. Unfortunately I had to rebuild it the second time without him. His specialty was tuning exhausts.