As with my air cooled & watercooled street bikes mostly, I would get a bit curious (nervous at times as I would be a long ways from home) ...Just what is the temperature....is my bike running too lean.... is my bike running hot...Is my thermostat working properly...what if my idiot light isnt working right...ect ect. The solution was to remove the OEM dipstick, and find a temperature dipstick replacement....There, no more wondering....no more Off or On stuff. Now you have early warning these might be heating up!

Has anyone seen one that works with the Rancher 420 or any Rancher for that matter?

 

I think your best bet might be one of those temp gauges that splices into a coolant line.

Quality air cooled engines are a lot tougher than most people realize. Back in the 3 wheeler era, I used to spray weeds in a pasture, in temps up around 100. It amounted to creeping a few yeads, idling to spray, creep a few more yards...

I used to have a Buell Thunderbolt, and one time I took a back road back from Portland. We had record heat that day (the store I went by said 117) and I got stopped in one way traffic over fresh asphalt. With an engine tuned for way more power than it was intended, I figured it would melt down. It never missed a beat. I, on the other hand, felt like I was going to die.

 

Might be except if the water stopped flowing or ran short/low (which is a common cause for overheating) then you wouldnt get an accurate reading.

I have a Air Cooled 1900cc street bike, and I dont worry about aircooled machines, only the watercooled as there is more to fail.