Spiro, i believe there was only one size key. I have seen two different size keys used. The original or most common is a rectangular bar. The other is a common oversized Woodruff key. I have to assume the Woodruff key slots were cut to repair damaged crankshafts. Keep in mind I have only worked on or dismantled about a dozen of these motors from 1921-27ish. There are definitely three different flywheels that will fit, but again, those get changed all the time. I know for sure there was a change in 1926 to the dished “safety flywheel” with the big holes. The smaller holes came later. 1921 to 25 all use the same flywheel according to ELTO even thought my 1921 crank had a large Woodruff key. It also had a much later (and butchered) flywheel on it when I got it. The problem I find is that the best examples are stored away on racks in old collections. What we are finding out in the wild are beat up and picked over motors. These motors have lots of replacement parts from other years. Also, ELTO made a lot of subtle changes that you wouldn’t even notice from year to year. Hopefully, someone more experienced with Ruddertwins will chime in.
Wayne
Upper Canada Chapter
uccaomci.com
