Below is a thread of my experience with excessive heat on the Twin Cams, and what I initially did to solve it. YES, the heat was so bad that it ovaled out my cylinders, along with other damage. The amazing thing is that it kept running and was NOT burning oil.
Because the power degradation was over a period of time, I did not even realize it had occurred.
I have since met many folks that have experienced the same thing as outlined in the thread below.
http://www.triketalk.com/forum/threa...2011-Tri-Glide
After getting my engine rebuilt, under warranty, I have spent thousands of hours figuring out how to keep a Twin Cam in the optimum operating temperatures. Full report on that can be seen
HERE.
Regarding the M8, from all reports, it seems HD has done a great job at reducing the felt heat, time will tell if they have the actual heat down enough to prevent long term engine damage.
Kevin