Question

[hank43]

Here's a question for all you mechanics:

I used a FLUKE #62 digital infrared thermometer to look at the heat at various points on my bike engine. I got some surprises.
(The Fluke #62 can measure temps from -20 to +932 degrees F., perfect for this application. I tried to photograph the readings to show, but my cheap camera won't photograph a LCD screen)

1. Measured cylinders before starting engine (No surprise here, it was the same as ambient air temp, about 76 degrees)
2. Decided to run engine taking temperatures at various times and places until the fans kicked in. Here's the surprise

At one point, the bikes temp gauge registered 1/2 way. the upper radiator hose measured about 176 degrees, front jug measured about 216 degrees at the fins just above the exhaust port. Measured rear cylinder in the same place, it was 40 degrees COOLER. What? Rear cylinder is cooler??? I would have thought it would be warmer, because it is behind the front cylinder........Is it possible that Kawasaki mixes the air/fuel a little more towards the fuel side, to prevent the rear cylinder from getting too hot? I would think this possible if cylinders fired at different times, the ECU could just give the rear a little more gas....??

3. When the fans both came on, the top radiator hose measured about 205 degrees, this would seem to me like the thermostat is working ok, as I am seeing greater temp changes, because coolant is now flowing.
4. I let the engine idle several minutes longer, I did not see any increase in temperature on the cylinders, nor did I see any less temperature. Looks like cooling system is functioning as advertised.

5. I did note that the exhaust pipe heat shields did not get any hotter than the cylinders, but they did get that hot. I wonder what they would be without the wrap? Would they be cooler because the air could pass between the shields and the pipes, thus carrying more heat away?

Comments, anyone? Anyone else have a temp gauge they could use on their bikes?

Hank