I know I'm a noob and all that, but why is this post in the Zero motorcycle section?
I agree, but I understand why. Francois is a 2014 Zero SR owner and has had motor overheating issues.
Francois, have you tried riding the 2016 SR with the IPM motor? You can still overheat it, but man you really have to work really hard to do it. I say this to everyone, but upgrading the 2014 to a 2015 bike or newer will give you many more advanced features that I consider essential if you ride everyday: Better wheels with stronger bearings, better suspension that is fully adjustable, better brakes with ABS, and of course better battery range.
Although for you, moving to a 2016 is important as that is when the Interior Permanent Magnet motor design that runs cooler became available, and of course I know that is your primary concern. Also with 2016 you get yet another battery capacity increase. So you would go from 11.4 kWh to 13.0 kWh or a 15% increase in range for the same weight! This is huge!
The parker motor looks very impressive, that was a long PDF but interesting. However it doesn't fit with Zero's philosophy of sophisticated simplicity. Using a motor like that would require liquid cooling and between the motor cost and coolant system design perhaps raise the cost of the SR by $3000-$4000 or more. Since cost is the biggest barrier to electric motorcycle ownership right now, I think Zero is on the right path with the current motor design.
Just like every 2-3 years we see a big battery increase or power increase, I would expect that would continue. But again for now if the bike you have is a 2014 Zero or earlier, or you don't have one yet, moving to a 2015 SR, or 2016 SR if you need max range and have higher sustained power requirements is the best thing to do.