I actually never got around to doing mine yet. Probably going to do it as soon as the cold winter months start here because it will be to cold to ride.
What my plan is and I have no idea how it will work. I plan on cutting these heat sinks into smaller heat sinks to fit against the inside of the stator.
You are probably asking how will they fit the curve of the inside of the stator. Well, once they are cut down, I will cut slots in the back of the heat sink every 3-5mm, this will allow it to bend into the circle.
I could even easily mill down the bottom of heat sink to make it thinner and easier to cut, no reason to have a thick bottom as I am looking for surface area and not thermal mass.
I already bought some thermal epoxy which supposedly bonds aluminum heat sinks almost permanently.
HOpe this is understandable. The way I see it is that as long as I get a decent amount of contact area it should transfer most of the heat, doesn't need to be 100% efficient like a CPU.
I like the heat sinks I posted the link because the fins are very long to give maximum surface area. I can also bend the thin fins easily to adjust to being bent into the circle.
directing the airflow through these fins will be important. Knowing that the stator takes in a tremendous amount of heat this should easily pass that heat into these fins. With airflow going through these fins it should cool the motor so much better.
http://www.ebay.com/itm/150x69x37mm-Heatsink-Aluminum-Heat-Sink-Heat-Sink-for-LED-Power-Transistor-/281199490524?hash=item4178cbb5dc:g:IJsAAMXQWzNSc6rr
