Thermo-Bob

You know how it goes. I am a car and bike tech geek, but sometimes, it takes me a long time to figure out how something really works. In this case, it the cooling system.

I remember back when I "upgraded" Gidget's engine. Since I was living in warm California and had increased the horsepower by about 75%, I figured I better put in a better radiator and fan to keep Gidget cool. Well, it turns out that Gidget has one of those thermostats with a bleed hole in it to keep a little coolant circulating all the time. In the summer, there isn't any kind of coolant bypass since you shut off the heater. I always wondered why it took so long to get the coolant temp up and why you had to run a little choke all of the time, unless you were running her hard. Now I know that the little bleed hole was letting coolant into that nice big radiator and circulating cold water back into the engine, even when the thermostat was closed.

I got a better understanding of this when I replaced my KLR gauge pack with an Acewell instrument computer. The temp gauge on the Acewell couldn't use the Kawi head temp sensor, so I had to put an Acewell temp sensor into the top radiator hose. Imagine my surprise when the temp gauge read 135 deg F on a warm summer day. The coolant temp also varied a lot, bouncing around even when just riding down the highway.

It turns out that the KLR has a pretty big radiator because it has to cool the engine under high temp, low speed off-road conditions. In the stock system and under highway or cold weather conditions, the thermostat stays closed until the coolant at the top of the cylinder gets hot enough, then it opens allowing very cold coolant into the bottom of the cylinder until the thermostat closes again. That means that the cylinder is cooler than thermostat control temperature on average and that the temp is oscillating between cold and warm.


The temp history shown here is for stock system on on a cold day by the inventor of the Thermo-Bob. The Thermo-Bob is an external thermostat with a coolant bypass that circulates coolant without going through the radiator when the thermostat is closed. The blue line, inlet temperature, shows how cold the coolant coming into the cylinder can be and how the thermostat oscillates in its control.


This schematic shows how the stock system works, followed by a similar schematic of the system with the Thermo-Bob. By creating a coolant bypass of the radiator and thermostat, warm coolant circulates continuously. When the thermostat opens, a controlled amount of cooler coolant mixes with the bypass coolant, making for a warmer, more consistent coolant temperature. If you think about it, this is the same approach as modern cars use where the heater flow acts as a bypass. Maybe I should have soldered up the bypass hole in Gidget's thermostat and left the heater valve open.


This graph shows the inlet and outlet temperature traces under similar conditions with the Thermo-Bob installed. Notice how much smoother and better controlled the temp traces are. The hope is that fuel economy will be a little better and oil temperature will be a little higher and more consistent. At the very least, my temp gauge will register correctly.


Naturally, I ordered my self a Thermo-Bob. This picture shows the Thermo-Bob installed on a KLR from a web site picture. This guy has a Trail Tech instrument computer, so he had to install his temp sensor in the radiator hose along the side of the engine. I had to do the same thing, except my Acewell sensor adapter was far too long for this location. I cranked up the machine shop and made myself a version that saved about 1" on length.


Although this aluminum is nice and shiny when new, I realize that raw aluminum will eventually tarnish, so I'm trying something that works pretty well no raw metal of machine tools. Instead of anodizing or painting it, I "polished" the aluminum with car wax. I leaves a shiny and durable coating that I hope will keep oxidation at bay. We'll see.



The Thermo-Bob works as advertised. The temp gauge reads a nice steady temp in a range of temperatures and subjectively, the bike warms up a little quicker. I'm looking forward to a trip to see if I can tell any improvement in gas mileage.

Peak-esse Pay-awk

Pikes Peak!

OK, I know I don't bring any new constructive information when I just post a video like this, but man o man, this is just too cool for school. I love the feeling of speed over the dirt section. Watch him fight the bike on the rough section.

This is a nearly stock Ducati Multistrada 1200. It costs something like $18,000! On one hand, what a way to risk such an expensive bike. On the other hand, how impressive is it that such a heavy bike can do this and isn't this what the engineers had in mind when they developed the bike? Enjoy.

Greg Tracy - 2010 Ducati Multistrada Practice Run - PPIHC from greg tracy on Vimeo.

The Pass

Check out the pass of the #3 bike over the #1 bike. Holy moly!



Maybe electric bikes aren't so bad?

Honda Innovation

Last weekend I went to a mini-tech fair to ride the CuMoCo electric scooter. That was interesting and fun. In addition, there were a bunch of high school competition robots with their unusual approaches to steering. That reminded me of this video which explains some of the novel approaches being used in robots today. The interesting question is if this type of thing would ever make it into cars?

A Rant on GPS

It seems to me that these days, we rely on technology and miss out on seeing the world. GPS is a great example of this. Sure, if you are in a strange town and want to find a gas station, ATM, or restaurant, turn on your GPS. It will give you a little knowledge and get you to what you are looking for. But it won't be local knowledge. You will never know about that little eatery with its great special dish. You also won't have the pleasure of a little conversation with a local who loves their town.


Now on the motorcycle, I find it hard to read a GPS when I'm riding. The screen is just too small and you can't see it well when the sun is shining bright. In the car, its easier to see, but you get such a small view of the world, either no detail when zoomed out or just a postage stamp of local countryside when you are zoomed in.

I suppose you can try to plan your route before hand and follow the directions given by the little electronic voice, but you loose the pleasure of looking to find your way, find your turn, understand something of the country. In the end, you become an automaton blindly following directions and not thinking for yourself.

Of course, if you want to go anywhere but the largest freeway route, you can't plan a trip using a GPS. Any attempt to go backroads in fettered by the dreaded "Calculating New Route". Also, you can't see enough of the world to imagine your way across the countryside. You need a map for that.

And then there is the adventure of getting lost. In this case, GPS is just too helpful.

In contrast, consider the map. Lovely, multi-color printing, perhaps with land contours suggested by shading. A broad scale of the country that lets you understand the flow of the roads and their relationship to the land.

When you deviate from the roads on the map, you have a sense that you are between this road and this other road. That you are north of the river and south of the lake. Even when you don't know where you are, you know you haven't left that zone. So you just keep going until you reach one of those boundaries. Of course, sometimes its useful to have an idea which direction you are going. That brings us to my latest addition to the motorcycle. A $3.00 compass. I think the compass and a good map will always give me more pleasure than any GPS ever could.


On the motorcycle, I still can't read the map while riding, but if I'm going to stop and plot my course, I get so much more understanding out of a map.

Maps themselves are art. Even when I'm home, I can sit and look at maps for hours. I think of them as paintings with places to go. I love the names of these strange places along the way. More than once, I've used the internet to try and discover the history behind the name of a place.

So here is to maps, especially the paper kind. Although they may be headed for extinction to be replaced by mind numbing GPS, I hope they last long enough that I will be gone before they are. And to all of you, get out there and explore. Follow your nose and bring along a map if you need it. Leave the GPS behind and use your mind.