These measurements were taken today at Bill Chapman's home in La Quinta,
Calif.  The motor and pump of his 1926 Marshall & Wendell Ampico upright
piano are original:

  pump pulley: 15.25 inch outside diameter
  motor pulley: 1.75 inch outside diameter

  Motor made by Westinghouse for Ampico
  Style FS21012,  Ser. No. 3499393
  1/12 HP (Yes, 0.0833 horsepower = 64 watts output!)
  1140 rpm,  60 Hz, 1 phase
  110 V,  1.9 Ampere

If an original player piano motor cannot be found, a satisfactory
substitute might be a new 6-pole motor (ca. 1140 rpm) designed to spin
the squirrel-cage blower of a large evaporative cooler ("swamp cooler")
installed in a window frame to cool a large room of the house.

The motor hum will be reduced if the motor is operated at reduced mains
voltage, e.g., 100 volts instead of 120 volts.  Just be sure that the
motor starts okay and attains proper running speed.

Robbie Rhodes
Etiwanda, Calif.