Hello and welcome to my web site. My name is Bill Bath and I am the Gadget Engineer. I am a Mechanical Engineer living in Houston, Texas and for more than 40 years I have been designing and inventing new machines. Most of these machines have been related to the offshore oil business and to nuclear waste clean-up, but the kind of machines I like the best are classic British motorcycles and robots.

In 1968 I designed and built a class-winning micro-midget race car. I was 22 years old with a high school education, half a year of college, and no engineering training at all. My only useful experience came from a few teenage years spent keeping a series of Cushman motor scooters and later an Indian Woodsman motorcycle in good enough condition to get me to school and back. I was in the third year of a four year tour in the Air Force, stationed at Ramstein Air Base, Germany. As luck would have it, the base had a micro-midget club and a 1/8 mile paved oval race track. I unexpectedly became the owner of a Class B micro-midget racer due to a friend’s accident with my Mini. 

That car, and all the other cars in its class, were made using junkyard parts from Goggomobils. The Goggomobil was a German microcar built by Hans Glas Gmbh, in Bavaria. Beginning in 1955, this little car had 250 cc, two cylinder, 2-cycle, motorcycle-type engine built on an aluminum crankcase that included a 4-speed transmission and a differential. A simple universal joint connected the differential to a short axle with a 4.80 x 10” wheel on each side. For comparison, the Mini I owned at the same time also had 10” wheels but they were wider. The Goggomobil engine was mounted behind the back wheels in the style of Volkswagen and Porsche. The front suspension consisted of a pair of Y-shaped frames pivoted at the forward center of the car, each holding an stub axle and a spring loaded shock absorber. This arrangement provided a rudimentary independent 4-wheel suspension that worked well for a car with a top speed of less than 50 mph!

All the cars in the club were designed in the style of American oval track racers. In this style, the driver sits upright toward the rear of the car with the engine between the driver and the front wheels. This style fit well with the Goggomobil powertrain because the driver’s legs could be out in front and the engine could hang out the back. I can’t remember actually racing that original car, but I remember so well that I had just seen the movie “Grand Prix” and I was determined to build a micro-midget in the style of the Formula 1 cars in that movie. 

One thing I noticed right away is that the engine in a Formula 1 car was between the driver and the back wheels. It was obvious that this provided much better weight distribution than having the engine hanging out the back.

I was reading a lot of motorcycle magazines around that time and somewhere I read about a motorcycle with a sidecar that had something the riders called the “secret reverse.” The article stated that with the engine idling very slowly, the manual ignition timing could be slowly retarded until the engine would stop turning in the normal direction and would actually start running in the opposite direction. This is possible with a 2-cycle engine because there is no valve timing to require reversing. All that is needed is to set the timing on the other side of top dead center.

So, the first thing that went into my design was to mount the engine ahead of the back wheels and to run the engine backwards. The second thing was to make a laid-back seating position so that I could stretch out in the car and keep the center of gravity as low as possible. The third thing was to put the pedals out in front of the front wheels, in order to put my 200 pound weight as close to the center of the car as possible. I made a simple hand sketch, got hold of some lengths of 3/4” water pipe, and went to work. I had to overcome a few obstacles, like making a shifter linkage that would work from the opposite direction of the shaft that shifted the gears and making a major change to the front suspension. There were a few other things but somehow I worked them all out.


The simple pivoted front suspension design of the Goggomobil had a basic design flaw. Because the axle was fixed to a frame that pivoted in the center of the car, the camber of the wheels would change radically as the wheel moved up and down. In other words, the top of the wheel would lean in when the wheel goes up and lean out when the wheel goes down. I noticed that starting in1965, Ford pickups were using a twin I-Beam front suspension. Basically, they used a single solid axle for each wheel and pivoted the I-Beam on the opposite side of the truck. Using that idea, I modified the Goggomobil Y-shaped axle frames so that I could pivot them on the opposite sides of my racer and be low enough that I could pass my legs over them to get to the pedals that I mounted out in front of the front wheels.

Another problem that cropped up was that the Goggomobil engine was designed with a forced- air fan cooling system. This didn’t work so well with the engine running backwards so I designed some big air scoops on the sides of the car to channel as much air as possible onto the engine’s forward facing cylinders. It’s hard to say how effective this really was because a set of pistons would only last about 3 or 4 race days before breaking up. Of course, running the engine wide open in 3rd gear all the time didn’t really didn't promote engine longevity.

Each race day started with time trials. The six fastest cars then raced in the Trophy Dash, with the fastest car in pole position. I won a lot of these races because I had the fastest car and all I had to do was stay on the track and not make a mistake. After the Trophy Dash, there was a 20 lap race and a 30 lap race leading up to the final 40 lap race. These races were all done in what was called Australian Pursuit. For these races, the fastest cars were lined up at the back and the slowest cars at the front. This made for better spectating because there was a lot of passing as the faster cars from the back worked their way past the slower cars at the front. It also gave the slower cars a chance to lead the pack and the possibility to win, although I don’t think that ever happened.

So every race started with me in the very last position in the starting grid. The cars would be push started and the pack would make a couple of laps to get up to speed and get all the cars bunched together for the start of the race. After the start, I would always hang back on the first couple of laps because there was always the possibility of a crash in front of me. After the second or third lap, the cars would start to string-out into single file and I would start moving toward the front. My car was not a lot faster than the other cars but it handled better and turned a little sharper. Unless I was stuck behind a slower car, I kept the throttle wide open throughout the whole race. My style was to cut the wheel very sharply going into the turn so that the back of the car would slide out a little and point me straight across the center of the 180 degree oval. Then I’d power out onto the straight, gaining speed and rpm to prepare for the next 180 degree turn. If I could get beside and inside the car ahead of me while going down the straight, I usually come out ahead on the next straight. This didn’t always work. If I was the outside car in the turn, I just didn’t have the horsepower to pull ahead on the straight. The other car and I would just go around the oval like horses on a carrousel. We would go around this way for a lap or two before a slower car got in the way or the other driver made a mistake and I could break free and get back to my fastest line. 

Of course, it wasn’t always easy. The biggest danger of losing came when I would start lapping slower cars. It’s so easy to get stuck behind a slower car while the car behind is just waiting for this mistake on my part. It took careful planning to swoop around the slower car so as not to lose too much speed and more than once this tactic didn’t work. Also, sometimes the engine would blow or someone would crash in front of me. I won a lot of races and took home the B-Class Championship Trophy that year. I was a hero in the club and they gave me a nice going away party when I came back to the states the following year.

My '69 RE Interceptor and '01 Bonneville
Mower Gadget (before adding electronics)

I don't ride anymore but I still enjoy going to classic motorcycle rallies and my Motorcycle Stories page describes some of the best events along with pictures of the bikes. These stories include rallies in Texas, Daytona, Mid-Ohio, and England.

 My Robots page is dedicated to robot events and my current project the “Lawnbot” robot lawn mower. I hope you will enjoy my story of the Battle Bots in Las Vegas.

I think that home-built motorcycles that combine existing components into new and unusual machines should have special recognition so I have created a Motorcycle Specials Page to showoff the best ones that I have seen. 

Finally I have listed the patents that I have been awarded and the technical papers and magazine articles that I have written on my Professional Recognition page. The information on this page is presented simply to provide some background into my engineering experience. 
I hope that you will find something of interest in these pages. If you are working on an interesting motorcycle or robot project and need a “reality check” or a bit of mechanical advice then send an email bill@gadgetengineer.com and maybe I can help. Be sure to include a description of your project and some indication of your experience level.


If you have a “Special” bike and would like to display it on my Motorcycle Specials page please email some photographs and a little history or description of your Special to bill@gadgetengineer.com . I’ll be happy to add it to the page. If you see a picture of your bike on this page and want to add some history or information please let me know. If you don’t want your bike’s picture here then let me know that too.


THIS SITE UPDATED: July 24, 2021