I was wondering if anyone had any ideas on why the temp guage would stop working?

 

thermo sensor gone bad. its beween the frame and carbs. to remove drop engine, and then unscrew then install new. part no longer able to be bought new, check ebay or local junk yards. i had to replace mine, but broke it off in the block. so i had to drill and tap the thermostat houseing to hold the use one i got. it now works

 

So are there any early signs of a bike overheating, or should I stop riding until the sensor is replaced?

 

you could get a after market temp plug (advance ect...) and just clamp it on to the termostat houseing (under the right fairing) and then run the gauge up to were you can see it. it wont work great but it will at least give you a idea as to whats going on. the fan should come on at or around 140-180.

 

At what temperature would the bike be running hot. I heard my fan come on for a few seconds after it sat running for a while and I shut off the engine. I was just wondering if this is normal.

 

yes thats normal, mine hovers around 160 (thermo opens) to 180 and stays there at and about 170 the fan comes on.