A quick sketch showing the design error.

REMEMBER: I SAID QUICK!
This is NOT to scale. I did this in about 5 minutes to try to explain to an owner how the issue works. (Well- doesn't work.)

60 degrees today!

60 degrees today!
168 Km trip.
Needle just slightly (about one-half a needle width) higher than 40 degree day's ride last time.

Left the bike idle. Gauge needle would reach just the top of the face screw, fan comes on, needle drops to about 1/4 white, fan goes off, temp goes back up.

Everything looks good.

Antifreeze level is about 1/2" lower than the reservoir lid. This way, if it starts to get hot and overflow, I'll see it RIGHT away.

40 degrees today

40 degrees today.
210 Km Round Trip.
Needle never passed 1/4 white.

Today

Today

Still going strong.

Still going strong.

Twenty eight degrees this morning.g...

Twenty eight degrees this morning.g...

Says it all

Says it all