Wandering temp gauge?

Went for a super long ride yesterday - it was awesome, but I did notice 'interesting' movement of the temperature gauge.

Was a lovely cool (<15C) day, and this was on the open road (~120kmh) so lots of cool air rushing through the radiator, I was the lead of two riders and no, it was not due to sitting behind traffic - there wasn't any.

I noticed that occasionally the temp gauge would wander up a bit, 2 or 3 mm above what I consider to be 'normal'. Not as high as the fan switch-on point. Then quite rapidly it would move down (you could see the movement even glancing while riding) to maybe 2mm below 'normal' and hang around there. It was not continuous bouncing up and down, occasionally staying down sometimes settling around normal and all looked fine. But it happened often enough to spook me a bit.

The only conclusion that I can draw is that the thermostat is on it's way out - instead of opening smoothly, it is sticky and clicks too far open a little late?

I'd be interested to hear if there are any other theories?
{ZZR1100D, but I don't think this is a bike-specific problem}

(-8

or a poor electrical connection

Its the thermostat opening and shutting. No big deal. Look at it less and the road more

Thanks guys - thermostat on order, and I'll replace the coolant at the same time.

I'll post up if I find any visible issues ...

(-8

I get that on my ZZR1200, it is just the thermostat opening when it should, probably no need to replace it yet.