I removed a pulley from my CS1, to put on the other (exhaust) side for driving an alternator.
The key was a loose fit, so I made a new one on my mill/drill.
I was surprised to find the keyway on the crankshaft measures 14mm wide, not the expected 9/16" which is slightly wider.
At first I thought it just wanted some dressing with a file, to remove burrs that made it seem narrower.
But, it really does seem to be 14mm, with no discernible lip after cleaning it up.
It even measures 14mm at the bottom of the keyway, at the extreme end of the crankshaft, so it's not just because of deformation.
I reduced the width of my new key for the part that engages the crankshaft groove, the only way it would fit - OK now.
Is this really a metric sized keyway?