So, I bought a stock GY6 starter motor ($27) that was exactly like the Ambassador motor except for the lack of mounting bracket and screw drive instead of hub mounted on flat sided 1/2 inch shaft.
Took the armature and the front end and used my case with mounting bracket to marry it... Worked fine. Now to adapt the flat sided half inch bore timing belt gear to it which also was screwed into the end to retain it.
I built of the geared shaft of the replacement with JB Weld and drilled out and tried to tap the shaft for the 5mm screw. Drilling went well, but Irwin Tap broke off after about 1/4 of the way in.... used their suggested 19 drill... Darn it! now I am screwed..
Went with plan B and free hand ground down the flats on opposite sides of the built up shaft and timing belt pulley slipped on nicely. No screw to retain so i went with the Bearing "thread retainer" glue I bought for the CVT shaft.... it worked fine.
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