OK - but Castle has only made a 1717 with two kv ratings (1580 and 1650) - does it work with both of those motors?

The answer that has been established by the President of Castle Creations in this thread is "NO".

I don't know why you are trying to respond to me with some technicality - the bottom line is that if someone buys this for the 1650kv version, they're not going to be very happy. And your eBay ad is still misleading.

Its only sense that if the stators are the same , The rotor will work . However your motor will be gimped . At least thats what castle support explained when i begged for a repair kit.

That's not exactly true.

The kV is inversely proportional to flux in the air gap, so weaker magnets = higher kV, stronger magnets = lower kV.

And by the same token, smaller air gap = higher air gap flux = lower kV, and larger air gap = lower air gap flux = high kV

And the new 1717 is completely different -- different stator, different rotor diameter, etc.