That rotor looks out of proportion.

 

Yep your right, that rotor is larger in Diameter than 10A,12A and 13B. It's Mazda's only "stroked" rotary. Fantastic low end torque from these engines.

 

What can I do that would stop teasing?

 

Everytime I look at the size of that apex seal, I can't help but..............
I've read about the size of them , but seeing them is a different matter alltogether.
Nice find!! (however you got your hands on it)

 

Those apex seal's are common. Same as 10A Thank-fully Being made of carbon they dont tend to scrape the inside of your rotor housings but best of all they have great sealing qualities.
Unfortunately they just dont last long enough, and the side seal's are obsolete.
I'm very lucky and pleased to have located this spare 13A engine and gearbox right here in New Zealand of all places after a valuable tip from Australia on another mazda forum site.
Unfortunately (for me) the rotor's are being sold off to another enthusiast to assist restoration of another Luce Rotary Coupe but I'm keeping everything else for spare's. Who know I might need them one day.