Hey anybody know of a wrong sender or other fault that would make my bike run cold on the gauge? The rads are hot and i can see on the water temp gauge when the thermostat opens but its only just 5-10mm off cold on the gauge? Could a previous owner have fitted wrong sender or other electrical gremlin to find?

Sender could be stuffed. Honda service manual has a test for the gauge, says disconnect sensor wire and ground it. Turn on ignition, gauge should go full scale, remove ground within 5 seconds to prevent damage to gauge.

To check sensor, place in a container of coolant and measure the resistance at various temperatures: 50 deg C, 130-150 ohms; 80 deg C, 45-60 ohms;120 deg C 10-20 ohms.

Hope this helps.

normal running on a good system will only see the temp goto around 1/4 of the way.
never seen mine over half way and that was stuck in traffic in spain.