Hello jmadden91

A warm welcome to these forums.

Yes, parts for thoroughbreds are getting thin.
That's a shame because it was a solid, competent design.

So, you are talking about the small drive sprocket at the top.
I'm hoping a member will be able to help here.
I guess the main issue is internal diameter and number of teeth.
https://www.outdoorking-forum.com.au/index.p...th=1_17_346_348_394&products_id=5233

If all else fails, an off-the-shelf sprocket from a bearing
company might be an option.

Hope this helps.
-------------------------
Jack