I wasn't sure where else to post this as it's not really a "DIY" for most people. I first saw this done on a youtube video by RotaryEngine.com where Adam casually mentioned this mod they perform when porting. At the "top" of the exhaust port is a shelf left over from the machining process. Adam explained that as engines run, carbon can build up on this point and eventually break off and make the engine sad. After the coolant seal failed on my motor, I pulled it apart and it turns out Adam was right; I found a fair amount of carbon build up on this area in my motor. I decided to eliminate the possibility of future carbon buildup on my motor and went through the smoothed this area out. I took pictures as an example of the pre and post smoothing. To be clear, I did not port this motor or mess with the port timing, this was merely a smoothing activity on the port. Just thought I'd share with the group.