Hi Max. On the original shaft the machined area where the rotor fits that length is 54mm, on the shaft I have the machined area is 39mm. Cheers. Maurice.
Probably need you to confirm if there is a Keyway cut in both ends of the crankshaft before going further.
The 38mm end of the shaft looks to have a split pin hole , for a castellated nut etc.
The 39mm end instead of the Rotomo 54 mm end ,it may have had a shorter shaft that end because if it was a boat motor (outboard motor) and had a cowl fitted it could use a different flywheel and a different starter ,possibly a recoil starter and that may explain the split pin hole in the other end of the crank to lock in a direct coupling via universal joint or flex coupler etc.
This crank looks like an industrial motor crank and not a lawn mower crank ,I've seen Victa motors used on cultivators and they don't use a standard lawn mower crankshaft. The cultivator crank has a Keyway cut on both ends of the crankshaft.
I've seen old Victa motors also used as inboard boat motors.
For this to be an Industrial motor crank I would expect the 38mm end to also have a keyway machined into the shaft but I can't see that in the images
Could just be from a batch of motors they were testing.
I've seen some pre production models and they have slight differences that they didn't go ahead with ,for mass production.
If there is no keyway on both ends of the crank and no taper on one end then it looks like it may have had a threaded hub that used a splitpin and a shaft or blade plate could have been bolted to the hub.
As I can't see a taper on the bottom of the crank for a blade plate hub ,it's possible it's an early Rotomo crank.(501 to 1246)
Number 1247 and on had the tapered crank end for the tapered sleeve (or blade plate hub)
No mention of the split pin hole in the paperwork so not sure if the factory drilled that or someone at home drilled the crank but if it was factory drilled you'd expect it to be a perfect centre hole.
Unless you find another original mower,outboard ,etc with the same crank it's difficult to say for sure what this crank was used for.
