So on the "what did I do today with my NC" post I mentioned I installed a Superlite RSX rear sprocket. Noticed something interesting after that post:

- Found a couple few failure reports online for the "R7" version steel sprocket, which is in fact what I ordered from their outlet, Sprocket Center. Failures were on liter bikes however, and all seemed to be getting used for track days or actual races. So I had little concern for a machine 100+ HP down and 1/2 the torque.
- Apparently the mfgr, Drive Systems USA, must have found some merit to these reports as I was shipped a RSX sprocket rather than a R7 (so the newer design). Cool. Figured it was the new part number 10509RX; invoice still had the older part number 10509R.
- But the sprocket is in fact stamped 12509RX. Perfect fit. No issues. Nice looking piece. Didn't notice until I went back and looked at it today.

So what gives?

The 10509RX you will see on the parts lookup for the NC is listed as rated for 220 HP+.
The 12509RX is apparently being substituted for the listed part and is rated for 250 HP+. Listed fitment is Yam R1, 2015-18. One of the machines reported as having a sprocket failure.

Thought this was interesting. Despite some bad press, they seem to be taking steps to head off any further issues and look after their customer base to some extent (for whatever reason).

So, NC700X (so CB 500 F / X) have rear sprocket interchangeability with Yam R1. Could be useful when hunting different size by other manufacturers.

Obviously would order the 12509RX knowing this ahead of time if buying a Superlite; don't know if they will ship a 10509RX if you order one.