Originally Posted by scootertrash
I have a neat trick for a penny tech oil temp gauge from the FSSNOC magazine:
Remove the stock plastic oil filler cap and clip of the stick. Drill a small hole in the center on the underside where it comes through the center of the handle. Now drill out the handle with a 1/2" hole saw. Purchase a cheap oven temp probe with a round dial and epoxy it in the hole, making sure to tighten the cover and clocking the dial before the epoxy cures. Scratch a few marks on the probe for oil levels. You now have a cheap temp gauge at eye level.
White Bros. used to sell a temp gauge that was basically what you describe, and screwed in place of the plastic filler cap. I had one on my SR.