Started up my bike today after not having ridden for a while. Rode it around a little, came back to the garage partially warmed up. After killing the bike I swapped in a new battery, removed the kickstand switch (going to rewire it to be always "up" and then put the key in to see if the bike would start with the switch completely removed when. When I give the bike power the temp gauge shoots all the way over to the right, way past the red. Suggestions?

 

did you put the kickstand switch back in? i know it sounds unrelated but electronics can be fishy.

 

Is the battery connected properly? Reverse polarity could cause that.

 

does it go back to normal position as soon as you let off or does it ease back as the bike sits?

 

Yes, I did try with the kickstand switch reattached, it makes no difference. The battery polarity is correct. When I turn the key off the needle eases back to rest position on the left over a few seconds.

 

Under Idle the gauge stays in control, its only on throttle response right?

 

I haven't started the bike since the problem began. I tried a little while ago but it didn't want to start (could this be due to the kickstand switch? I thought it only cut the engine when the bike is put into gear?). The gauge goes up to maximum when I apply power on with the key--as in electrical power only. Also, the gauge does take a long time, maybe 15 seconds to go back to resting position.

 

I would suggest you go carefully over what you changed .Try putting every thing back as it was. Then look for what you may have touched or moved in the process. I dont know the wiring diagram, but I think it's posted in this forum, sounds like something is grounded or open from your experiment.

 

It turns out the body of the kickstand switch needs to go to ground for the temp gauge and dash lights to work properly. I grounded it together with the appropriate wire and everything works as though the stand is always up.

 

Clearly you've never ridden off down the road with your sidestand down and ended up in the bushes. If you had, you wouldn't disconnect your warning switch....
But each to his own !
At least you found the problem.