The Story Behind Kevin DeShazer’s 3 Cylinder Radial Engine

Recently we put up a couple of photos of Keven DeShazer’s three cylinder radial, a fascinating mix of motorcycle and aero engines combined into his own unique design. There was no way I was going to let this go without finding out more about it and I asked Kevin if he would tell us some details of the background and include photos of the earlier stages of the project. He was kind enough to send back some interesting shots, a couple of videos and a bit of the background of how this engine and motorcycle came to be.

When Kevin started, he expected to put about a year into the engine and another year into the bike, … that was in 2004. Of course, it’s easy to understand how he misjudged the time he would need since this is his first engine and first bike project!

As Kevin notes below, he has carefully saved his CAD files and documented the whole project so the engine can be duplicated, whether he wants to build another one himself or, since there’s no casting required, might be a challenging project for another builder who knows his way around some machine tools.

Maybe the best thing is to let Kevin tell you about it himself:

As a child, I tried to convince my father to buy me a non-running Indian motorcycle for 25 dollars but he refused, hoping to dislodge this obsession from my young mind. I didn’t own a motorcycle until years after I left home. So maybe I am still rebelling.

I read that the Vincent engine designer worked for a radial aircraft company prior to creating his own beautiful engine. And didn’t the Harley Davidson twin begin life as two cylinders off a radial engine?

I wanted to build my own bike with my own unique engine. I knew it was a tall order. It had to be big, 2400cc, and it had to be light and handle well. I hoped the engine would also have the ability to fly a plane. And it had to sound fantastic!

I heard an Italian in broken English describe what emanates from a Ducati: “It’s not a noise, issa “sound”” and I enjoyed the sound emanating from my Ducati and Guzzi over the decades. This video captures the sound as many viewers commented. Imagine the “boom” standing behind a radial engine with the Harley cam timing. I made it a reality.

Three cylinder radials were made in the very early days of aviation and then again for a limited number of Piper Cubs but they were a Top Dead Center cylinder arrangement. Rotating it into a “Y” configuration would prevent the cylinder head from scraping while leaning on a motorcycle. The Y is also visually endearing and actually makes me think of a beating heart. There are some issues having a cylinder Bottom Dead Center and I now know why it is avoided.

I began working on this project in 2004, designing it in 2D CAD. I wanted to design a beautiful and unique engine. I bought a milling machine for the primary purpose of this project and later a lathe. The engine took me ten years but I must say that I didn’t work on it all the time. It started slowly and once I had all the parts made and began putting it all together, my time investment increased. I work on it most days now.

I designed my crankcase so that it consisted of machined plates that would be bolted together and sealed with O-ring cord. I carefully saved and documented all my work so that this engine could be duplicated. Only a handful of parts required CNC machining.

ISSUE #1 Heat and Oil in bottom cylinder
It took a while to figure out why my left cylinder always ran cool and the bottom cylinder ran hotter. I had allowed the oil to gravity feed to the bottom head but soon realized this not only caused excessive heat buildup but caused oil leakage into the bottom cylinder with the potential of hydraulic lock. If you look at this video clip of the first time starting the engine, you will notice a lot of smoke from the bottom cylinder. The answer was adding a small electric scavenge pump that eliminated oil accumulation.

ISSUE #2 Vibration
I have a vague memory of a college professor saying that radial engines are inherently balanced due to the odd number of cylinders, but maybe I was dreaming. In any case, I learned otherwise. Common practice is to take one row of 9 cylinders and offset it against a second row of the same to balance out each other. I spent a lot of time and energy researching just how to balance my engine but there wasn’t a lot of information out there and none of it was recent or applicable to a 3 cylinder. I did the best I could but when I got the engine running decent in respect to timing and carburetion, it would shake like a jackhammer at higher rpms. I tried trial and error and field balancing and I did make some progress but it was still too violent.

This video clip shows some progress made by bolting on small counterweights to the flywheel. I decided that I needed to redesign the heart of the engine, that being the master and connecting rods, by making them out of a Fortal aluminum (not steel). I also made hollow titanium piston pins and shaved as much weight as I could from the inside of the piston itself. All in all this reduced the weight of my rotating mass by 1/3, which is pretty HUGE. The vibration difference was very exciting and gave me the confidence to move on to the second part of the project, building the bike. The bike frame is about half way done.

Kevin is a 2 year trade school graduate and also has a degree in Manufacturing Engineering Technology. He now specializes in designing and building production machines. Currently he works as the Principal Engineer for a Japanese OEM automotive company.

Kevin has his sights set on entering the AMD World Championship Custom Bike Building Competition, and with a project like this, why not?

Some of the most impressive projects on The Kneeslider have this “I think I’d like to build a …” motivation behind them. Someone just gets an idea to build something, there are no instructions, no kits, just an idea and the desire. Then, often, many years later, the builder emerges and says, “Hey, take a look at this.” It is just so cool.