I picked up my D21B to tonight....the machine work on this engine is very good. For the price it is an absolute bargain! However, I do have one question......how are you supposed to remove the back plate??
The O ring that seals it is so tight that I had a hell of a time just rotating the backplate (yes....I did have the piston off BDC). The backplate sits completely flushed with the casing. In the end I had to rotate the backplate by about 15% and then use a screw driver, using the edge of the engine mount tabs to "pry" the plate off, little by little...ended up scratching the backplate a little on the mating surface
When I finually got it off it was obvious that either the O ring was too large......or the channel cut into the backplate was too shallow. I've never had this problem with the Nova or OS engines I run
I normally strip and clean the engine after each days run......I'm not really looking forward to this part with this engine!!!!