Vol. 26: Make a Motorbike!

Add a retro-style, one-cylinder gasoline engine to your bike.

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Bike Whizzer, from MAKE Volume 26

+ Make a Bike Whizzer
Add a retro-style, one-cylinder gasoline engine to your bike.

By Lew Frauenfelder

I was reading Boing Boing one day and saw a link to bikemotorkit.com. At that site, Gas Imports of Kalamazoo, Mich., was offering a bicycle motor kit consisting of a 66 cubiccentimeter two-cycle engine, drive mechanism, gas tank, muffler, and controls for $120.

The ad brought back kid-time memories for me, as I had dreamed of one day owning a Whizzer now I could make one!


Whizzer motorbike kits were introduced in 1939 by Breene-Taylor Engineering, a Los Angeles producer of aircraft parts and carburetors. The kit cost $55 (something like $800 today). People would buy these kits, which consisted of an engine, roller drive, control levers, etc., and adapt them to regular bikes. (Interesting trivia: a Whizzer was the only motorized vehicle you could purchase new during World War II!)


The Whizzer brand was revived in 1997, and today a new Whizzer sells for $1,400; the engine kit alone is $500. I decided to pay $120 for the Gas Imports kit and maybe $50 for a used mountain bike, and make my knockoff motorbike for a lot less money.

The kit arrived from China about three weeks after I ordered it. I opened the box to find that every nut, bolt, washer, and other sundry parts were not packed in tidy little plastic bags but were loose and had obviously rolled around in the box during its journey to me. I had no idea if parts were missing, as there was no assembly manual either.


I carefully laid out the parts on our laundry room counter and forgot about the mess for two years. After this lapse, I figured Id better get serious about building my motorbike, especially since my wife wasnt going to put up any longer with lost counter space.

I went online and found an assembly manual PDF and an assembly video at Gas Bike (gasbike.net). They also sell a variety of bike motor kits. From there, I went to Craigslist and spotted a mountain bike for $35. The bike was in pretty rough shape, so I overhauled it first before motorizing it.

Now for the coup de grce the engine and control mounting! Actually, the process went quite well. The kit uses a chain-driven sprocket that clamps to the rear wheels spokes. I found I was missing a part and readily located a replacement at a scooter shop.


Since the now-motorized bike has no starter, I had to get on, aim it downhill, let out the clutch, and hope it started. It did! A nice pop-pop-pop noise like a baby Harley came from the muffler. I turned it uphill and was amazed at the torque that came from that tiny engine.

Im looking forward to more rides. My only regret is missing two years of fun motorbike riding by letting the parts lie fallow instead of getting with it the day the kit arrived!

Bike engine kit forum: motorbicycling.com

Lew Frauenfelder lives in Boulder, Colo. When hes not building bikes, hes making stained glass windows, fixing stuff around the house, and trying to stay retired.

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