I had 2004 sb 700 and I put one on. The temps went from 120-140 in powder, all the way up to 220 when running in extreme cold temps and low snow (running a road, etc) Only packed snow on the running board one time, all season long. Normally it would be around 150 or so on a trail with decently loose snow.
It ran way cooler than my RX-1.
I saw another fellows setup. It was a nice digital job with programable temp warning, for high and low (flashed)
It costed about $55 for the sender and the gauge. All black with either red or blue digits.
Go to JCWhitney and plug in Cyberdyne. Find the gauge that is for water temp and the necessary sending unit.
I put mine in the rubber line (cut it into two pieces) close as possible to the thermostat. I took a piece of 3/4 copper pipe about 2 or 3 inches long, threaded it for the sender (after whacking it with a hammer to make a flat spot in the middle of the pipe where the threads went) then put it into the water line with hose clamps.
Need to solder a ground wire to the edge of the pipe, cause it needs a ground, then wired the hot side wire into the key switch. If you have a battery you are all set. If you have no battery you need to add a small rectifier from radio shack.
It was very nice setup and I never had to guess what was going on....ever.