One Wild Whizzer
by Harry Klessen
Most every young man’s dream in the late 1940′ s and a few years there after was to have a Whizzer motor installed on their bicycle. In my bedroom I had a large wall poster distributed by the Whizzer Motor Company. It extrolled happy people astride their motorized bicycles and suggested the freedom, power, speed, and gasoline consumption at 125 miles per gallon. In retrospect I think the motor and installation components came in one cardboard box with a price tag of $125.00. That was beyond my financial resources at that time, so my strategy became one piece at a time.
I already had a brand new fat-tired Schwinn bicycle purchased with money saved up from a newspaper route. My first Whizzer part was the heavy-duty rear stand to raise the rear wheel off of the ground. Later a large rear wheel pulley was attached to the spokes, which would be connected to a future engine by a set of pulleys and two v-belts. By using the regular pedal system of the bicycle and the belts, the engine could be turned over and started.
Eventually I purchased a complete used Whizzer motor and attachments for a sum of $50.00. My dream came true at that point, the freedom of a motorized bicycle. From then on as finances would allow, I tried to create the classic look of that era.
I hung the biggest bicycle mud flaps that I could find on the bottoms of the fenders. Then I added the largest possible variety of jewel reflectors to the flaps. I had the flywheel generator set with as many extra lights as it would power. To make the exhaust sound quieter I cut the bottoms out of two-quart screw-top cans and soldered the bottoms together to create a muffler to add on to the already stock system.
Another project for my Whizzer was a sidecar frame. I used electric conduit tube, with the ends flattened, holes drilled, and bolted it to the bicycle. No welding. A regular front bicycle wheel was the outrigger wheel. Not having a knowledge of sidecar geometry, I found that it kind of pulled hard to one side. I rode it to High School one day, but removed it at the end of the day. A homemade windshield was added for a while when the South Dakota weather cooled down.
From my Whizzer I moved upward to a English-made Famous James motorcycle with a 125cc Villiers engine. Then came a 350cc Triumph, followed by an Ariel Square Four (a square shaped 4 cylinders, two crankshafts geared together for 1,000 cc), and later a number of Japanese motorcycles of various sizes.
But I had given up my Whizzer at about the time my friend, Dale purchased one. The story of his Whizzer, which was inspired more by the hotrod ideal, was to be very different from mine.
Our hormones then told us that a fast motorbike was very macho. We knew that power to weight ratio is one of the keys to speed and acceleration. The easiest way was to strip off the useless weight on the bicycle; mostly fenders and whatever else could be discarded. Even if it didn’t help much in the speed or acceleration, it now had the appearance of a pseudo racing motorbike – the status symbols were still important. The best accessory that could be installed was a chrome, straight exhaust pipe made just for Whizzer motors. Now you had the looks of a racer and the sound of a racer. It rivaled somewhat the exhaust note of the big, single cylinder motorcycles back then. At high engine speed when the throttle was closed, a melodious back-rap emitted from the straight pipe.
In an effort to achieve a more motorcycle like appearance, my friend used a hacksaw to remove one side of the pedals crank. The remaining pedal was positioned with the original bike chain to activate the rear brake by pushing forward and down. Needless to say, this dictated the push, run and jump-on procedure to start the engine. I must say, he became quite efficient with this system. Another modification, ala British motorcycles, was to clamp on a short bar across the lower frame with handlebar grips slipped on for footpegs. Most American bicycles back then had very wide handlebars from side to side. To achieve a more racy look, the down-turned handlebars from an English racing bicycle were procured. They were installed upside down to curve up and backward. This also created the possibility that with full engine power and human force pulling back on the handlebars, you could pop a wheelie once in a while.
My friend Dale, who owned the stripped down Whizzer motorbike, thought looks and sound were not enough; he wanted speed. An easy power increase for a flat head motor is to increase the compression ratio. Off came the finned aluminum head from the engine. It was secured in a vise, flat side up. With a critical eyeball and a mill file, a lot of metal was removed to the correct amount. After that, being the perfectionists we were, the top of a plate glass showcase was used to true the gasket surface. Various full sheets and grits of sandpaper were taped to the glass. The aluminum head was slid back and forth by hand to remove the file marks and create a perfect seal. The cylinder head was secured to the engine and the flywheel was turned over slowly to see if there were any metallic sounds between valves and the head. This was one of many steps to increase performance of the three horsepower engine.
Hot Rod Magazine was popular reading back then and most of the fast cars had racing camshafts. The next logical step would be a racing cam for the Whizzer motor. The side plate was removed and the camshaft was extracted. With a bench grinder and a somewhat true grindstone, a judicious amount of metal was removed from the point of the cams. The flattened point would create a longer valve open duration. A critical eyeball was employed on the bottom of the cam to remove metal to create more valve lift. With new oil and a full race camshaft, the engine came to life one more time. During one of the weekly replacements of the 75-cent connecting rod inserts the camshaft was set one timing tooth ahead, which proved to be counterproductive. The rod inserts were replaced weekly as the crankshafts were prone to go flat, especially because of the use this engine had.
During one of the weekly overhauls the piston was extracted and modified. With a hacksaw and file the piston skirt was cut off, and a few holes were drilled in the skirt. The connecting rod was also drilled to cut weight. I think even one of the compression rings was left out one time to reduce friction.
Gear ratios can change speed or power; speed was the option in this case. In his high school wood shop, my friend created a wood replica of the double pulley system in different diameters for a high-speed ratio. The center ball bearing was inserted in the pulley, then the unit was installed and the drive belts tightened the proper amount. The engine was fired up, the clutch released and he sped away. Centrifugal force deemed it would be a short ride as the wooden pulley split apart across the grain. One modification beyond our abilities was to lighten the flywheel. A local machine shop was engaged to peel off as much metal as possible. With the flywheel reinstalled, we hoped it let the engine rev up faster.
Again taking our cues from Hot Rod Magazine, we noticed that most of the fast cars had at least two carburetors. The Whizzer engine had only one intake port, but this did not deter the installation of dual carbs on it. With hacksaw in hand, metal tubing and some welding, a “Y” manifold was created. Extra gaskets, hoses, linkages, etc. were installed. The dual carbs looked impressive and some fiddling with the main jet adjustment; it ran just fine. This was the last modification that we performed on the engine.
Our only measure of performance and speed increase was the speedometer on my 350cc Triumph as Dale rode his motorbike flat out beside me. I believe we probably created the most modified and hopefully the fastest Whizzer motorbike in our town.