I'll do it over the weekend or soon
Thanks, this is exactly the type of information I need and, oddly enough, close to what I expected. In addition it would be nice to know the hottest temp you can read from the radiator at the same time. Might be able to "point and shoot" the upper radiator fins through the grille, bet we're going to find a reading of around 85*
I think you decided that since you've got some air space around your switch the actual water temperature going in would be around 10* or so higher than the 70* switch you're using?
I did build that circuit and it does just behave like a switch.
I realize what I'm building sounds a bit complicated but it's easy enough to build and will have several advantages like an indicator that signals a fan fault or overheating as well as a remote temp gauge output for those popular dot/bar circuits. Besides that it's a gadget and I, like a lot of others, like gadgets.
Actually "not moving but fan on" gives me a pretty good low point, apparently the CX is quite happy getting 65* water back from the radiator if the heads were still that cool. Do you recall what the bike's temp gauge was reading at the time if you still have one?
I'm getting very close to having this on paper as a buildable device.