Was poking around in the M8 section to see how things are going with the new motor and I ran across this thread.
I posted a thread in the Twin Cam section related to the water cooled heads on my 2015 CVO SG. Although the project was about adding a water-cooled oil cooler to my bike the result was I learned a lot about the cooling capability of the twin cooled system.
http://sta-bul.com/projects/OilCoolerProjectPhase1.pdfThe water cooled "Precision Cooling" system actually works VERY well with a lot of unused cooling capacity wasted due to how it is implemented. When I removed the thermostat from the circulation loop I saw a 20 deg drop on head temperatures. And even after adding the water-cooled oil cooler into the loop the overall system temp was 20 degs lower at the valves and 10 degs lower in the oil bath. Not to mention that the system cools off much faster after a high load warm up event.
I was no "sold" on the wet head till I did this work. And the best thing about it is, if it fails your not stranded. Just ride on. It's probably the only good thing about it being a targeted cooling system instead of a 100% water cooled system.
The new M8s that are water cooled I heard have a variable speed motor on the pump. If you can find a way to get that pump to operate at 100% all the time I suspect you will be surprised at how much more cooling you will see from the system al of the time.
Check out the charts in the report I posted. You may find it interesting.
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