I've been wanting to do the watercooled head too , the cost has put me off , but would be an added benefit. Especially if you are riding long distances at sustained speed . And I also was thinking about the copper tubing idea and I believe that would help as well.
Earlier this year I looked into having a jug cnc'd that had water jackets machined into it , but the 1000 bucks was not gonna happen anytime soon .
Earlier this year I looked into having a jug cnc'd that had water jackets machined into it , but the 1000 bucks was not gonna happen anytime soon .