Robinr767,

I hope you did not follow the break-in instructions that came with your engine...

They were admitted, by OS' Bill Baxter, to be generically written for ringed engines and wrong.
This engine type (tapered bore; ABN in this case) must not be run four-cycle rich, while being broken-in.

Read this thread:

http://www.rcuniverse.com/showthread...59&forumid=145

Also read the OS Engines direct support forum in RCU.

The "freedom" you feel at TDC is normal and results from the intentional con-rod/wrist-pin/piston oil clearances, engineered by the engine manufacturer. It is even greater at BDC, but the lack of "pinch" there prevents you from feeling it.

Sincerely,,