Got the YD today. Full kit ,seems good quality have seen worse. Pulled the jug sure enough was piston backwards. If they are all like this maybe thats the correct way. Turned it around any way. Cleaned a small bit of flashing from the ports greased the gears, not a wisp of grease as received. Port matched the gaskets spiffed up the cylinder with a bit of black paint and called it done. Cylinder doesn't appear chrome but it is hardened. Rod has large oil reliefs. Mag appears better than most, sposed to be hi perf. Plate on motor is FBM came from Fast Bike Motors. Hope its not F in Bad Motors!
What I did find was the stud spacing on the jug is larger almost to the point the Stihl jug could be fitted, also the 12mm wrist pin may fit with a proper size bushing food for thought. May get a chance to try it tommorrow.