Camshaft woodruff key sizes

Camshaft woodruff key sizes. I have a 1974 R90 with a nutty history, another story, and the camshaft needed to come out because the PO used brute force when over tightening the small nut holding the advance unit on. He broke off the end. The cam I removed has a much larger keyway, maybe 25% longer, than the camshaft I thought I would use to replace it. And of course the woodruff key is larger both in length and just slightly wider. I think later in the airhead engines they did away with the key and the end of the cam is slotted. My question is how do I find a cam that will fit? What years did they use different keyways?
Regards,
Kurt

Kurt -

I'd suggest going to RealOEM and put in your bike and find the woodruff key...it appears to be part 07119951480 and the fiche gives the info "5x6,5". Using that part number in a reverse search on RealOEM and see the other applications. I did and it shows it be a common part on many models, mostly /6 and on. However, by looking at the R75/5 it shows the same part number.

I forgot about RealOEM, thank you! I am really wondering when they made the change to a larger key. The "replacement" I have is really a small little key, considering it's job of turning the oil pump I can understand the engineers bumping up the key size to make it a bit more robust. "Bumping up the key size" is probably not a common engineering verse!
Thanks for the lead on tracing this size thing down. I'll post what I find.
Regards,
Kurt (great name)