Glad the jug cleaned up well. You use muriatic acid and sandpaper? As for the piston, you might want to contact Dandikrop on fleabay. He doesn't have anything listed as an aftermarket 211 piston, but previously I gave him most of the specs and he wanted to know the distance from the top of the piston to the connecting rod, to see if he had something to match up - I never took it apart to get him a measurement. I'll see if I still have the e-mail to send ya.
The 211 is a strato type motor.Nothing else will come close to working.I will try to get a pic of it on here? LOL