Hey Matt,
My 3rd one is frozen solid. Heard it make a clank sound and stop. I've pretty much had it with this motor. Haven't touched it since it happened, planes been sitting in the corner for a month. I'm eventually gonna send it to hobby services without touching it and be told how its my fault.
Yes it's a shame that Hobby Services seems to assume that we are all inexperienced sport pilots. Then again, the vast majority of claims are made by them so I can see HS response.
I am curious though if your retainer let go. The only disassembly needed for that is removal of the large aluminum port screw and inspecting the piston pin's end. Of course if the opposite retainer let go, you won't be able to tell unless you took the piston completely out. If it's frozen then piston removal is the only option and would be best if HS did the work since they have the right tools. Heating the case with a monokote heat gun will help with sleeve removal. It doesn't take a lot of heat; hot water warm is good enough (120-130 degrees)
I priced the piston, ring, liner and retainers and that's quite pricy even with the 20$ Super Saver discount. I guess I will keep the remaining parts as spares.