Man, is the end of that wrist pin exposed to an open exhaust port? I've never seen anything like that on any two cycle engine. I was going to recommend that you obtain or have machined either teflon wrist pin retainers or brass wrist pin retainers (little buttons that fit on the end of the wrist pin) and lose the circlips. But, if the end of that wrist pin passes by the open port it would not be possible.

Bill