Primary shaft question

Good afternoon folks. 
I'm wanting to to put a later crank into my earlier cases but the primary chain gears are different width. 
Is the gear in the idler interchangeable or will I need a different shaft?
Thank you for any advice. 
Charlie. 

simoncharlton8@gmail.com wrote:

Good afternoon folks. 
I'm wanting to to put a later crank into my earlier cases but the primary chain gears are different width. 
Is the gear in the idler interchangeable or will I need a different shaft?
Thank you for any advice. 
Charlie. 

This is the crankshaft of my Z13 A1, it has more counterweights than an endocrinologist's scale.

As you can see, the width of the primary chain sprocket doesn't match the crankshaft sprocket you showed in your message.


However, it does seem to match the crankshaft you showed without counterweights at the bottom of the photo.