If you have an IR tester, check the temp at the radiator hose right at the thermostat housing. That's going to give you the most accurate coolant temp, which is what you want to know. On my 1100 Interstate, I can watch the gauge drop (slowly, sometimes) when the thermostat initially opens, as well as when the fan kicks on. Operating properly, on very hot days, with the fan running constantly, my actual coolant temp, measured right in the coolant at the radiator fill neck, is just under 200 degrees F. The gauge reads just under half, lol!
"He that is good with a hammer tends to think everything is a nail" - Abraham Maslow
"If you can't take the time to do it right the first time, how are you ever going to find the time to do it over?" -UnknownJosie, the farmer's daughter build
81 gl1100I barn find aka "Josie"
82 gl1100I Parts bike
79 Yamaha 750 Special, my sanity fix (right now!)New2U Bike? Read Me.