I don't dare test the rpm at high speed with the Starrett mechanical rpm meter. I read online it was never really intended to go much above 2000 rpm. To be honest, I have never run this machine at full high. I don't rout or shape on it (yet). So I don't care all that much about high speed.
What do you mean by "that 710 rpm? looks very reasonable." If you are referring to that last pic it corresponds to 825 rpm. That last pic was with the washer removed.
[edit] reread your comment, no, that pic is not 710 rpm.
[edit again] thinking about it, it appears that squeezing the idler pulleys together from one side (eccentric side) doesn't have the same affect as squeezing them together from the speed cam side, interesting. Perhaps that means it is more about the affect it creates on the motor sheaves? Perhaps having the washer in there is forcing the motor sheaves to actually close a bit more, increasing the pulley size, reducing ratio?
Mike -