~Since 2004~
A site about memories, thoughts, photos, and unrepentant opinions about motorcycles and motorcycling after four decades of twisting the throttle.

Tuesday, August 02, 2005

Aprilia Caponord: Hot & Cold

The water temp gauge on a bike tells you how hot the engine coolant is but what about the rest of the bike? How hot does the gas tank get? The bodywork? The seat cover on a hot summer day? All are warm to some degree and therefore are emitting infrared energy. "Gosh, Mr. Science..."

No doubt you've often wondered what your bike looks like in the infrared portion of the spectrum. OK, probably not. Humans cannot see infrared energy which is in essence what we call heat or at least some of it is heat if there's enough of it in the right wavelength. Yes, I know you can see the coils glowing on radiant heaters and other sorts of hot stuff glow also. We're talking about seeing low heat here (below 500°F) and temperature differences at low levels. If you can see how hot the body panels are on your bike you've got a serious problem in the works.

So if you want to "see" heat at low temperatures you need an infrared camera and it just so happens I have one at work. It's made by FLIR (same FLIR that makes thermal imaging goodies for fighter jets an such) and can in a single image measure over 70,000 temperature points and turn the temperature levels into pretty colors and those into an image that we can see with our own eyes. Cool. Or hot. I'll spare you the techie stuff about how it's done, it's tedious and involves math that I don't really understand myself; I just use the camera to do research on heat propagation through vehicle interiors and yes, that's every bit as exciting as it sounds. Zzzzzzz.

So I brought the IR (infrared) camera home to do a bit of work here on a test fixture and decided to make some heat images of the Caponord when it was sitting outside "cold" and then after it had been started and allowed to idle up to operating temperature of 168°F.

Below is the Caponord cold. It's Arizona in the summer and the air temp according to the thermometer on the Capo is a balmy 98°F.

In the visible light portion of the spectrum it looks like this:


The heat image (depending on what color palette you chose for the camera) looks like this:



Just out of the garage an into the Arizona summer sun.
Note which part got warmed up first even with the engine off.

 
The temp scale on the right of the image is in Celsius because that's what I normally work in temp unit wise. 60°C = 140°F just to give you an idea.
From an correct analysis standpoint to read the temps on the bike accurately you would have to know the emissivity of each material in the image and a few other details too. For our purposes here just assume the temps indicated are within about 2 - 5 degrees of accurate. This was fun in my driveway, not a NASA project, folks.
By the way, the aluminum frame spars and brake rotors appear to be cold because the angles and the highly reflective surfaces to some degree reflect "the sky" which is very cold or surrounding temps. No, not the air, the sky...different thing there...outer space as it were but not quite. Never mind. Just enjoy the pretty colors.
Here's the Capo after it has fully warmed up:

Engine coolant temp is 168°F at this point
The temps for the exhaust header pipes and sky are way off the scale hot & cold because the camera is set for vehicle interior temps and not engine type temps or outer space. Even the seat surface is past 60°C. More on that later. Note in the image the heat from the radiator coming through the body panel below the gas tank and the heat of the engine warming the concrete driveway. The camera, by the way, has a temperature sensitivity of as little a .07°C so it's possible to pick out some minute temperature differentials with the FLIR analysis software.

With the FLIR software you can look at specific points and areas in an image and figure out all kinds of interesting things about temperature movement and levels that most bike companies choose not to know or at least care much about. How do I know they chose not to know that stuff?  Because I've owned enough bikes that roast legs when idling and sometimes even when riding to know that no one bothered to test for heat issues as a consideration of rider or passenger comfort. I've heard that Yamaha's sport touring FJ1300 is a leg warmer. The Caponord is a bit too but not enough to be a bother. My old Yamaha 550 Vision was the all time worst here in Arizona. Just riding home from work on the Vision was enough to leave you stunned and dizzy and with 1st degree burns on your inner thighs.

I made a few more images of the Caponord and I'll post them next week for your interest and edification. They will be slightly more useful than the above two but not as picturesque.

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"When my mood gets too hot and I find myself wandering beyond control I pull out my motor-bike and hurl it top-speed through these unfit roads for hour after hour." - T.E. Lawrence



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