Suzuki/SJK Mini Free
1954—1959

I have tried to tell the SJK (Suzuki) Mini-Free (MF1) model history on this page as I know it. I would be grateful of any contributions — sales brochures, magazine ads, magazine articles, pictures, specs, facts, corrections etc. Please scan the material in JPEG format (large enough that all the details are visible) and send them to me. Please tell me the source and the publication date if possible. If you send me pictures of your own bike, please follow these instructions.

Part of a Mini Free brochure, I found the image on the Internet.

SJK (Suzuki Jidosha Kogyo) Mini Free (MF1). launched in 1954, replaced Suzuki's Power Free (1952) and the Diamond Free (1953) auxiliary bicycle engines. It was sold as an engine kit to hang on your bike like the Power Free or the Diamond Free but it was sold as a complete machine, being therefore Suzuki's first moped. It was also the last of the three cyclemotors SJK introduced in the fifties. Placing the engine under the frame for lower weight point improved the handling of the Mini Free. As one notable feature, the rider could switch between pedal- and engine-driven mode simply by operating the clutch lever. Its 50 cm³ air-cooled 2-stroke engine delivered 1.8 hp (1.32 kW) at 4,500 rpm, almost twice the what the Power Free, Suzuki's first bicycle engine, had delivered. Its claimed fuel economy was 70 km/liter and a it had a top speed of 45 km/h (28 mph). Mini Free was still very cyclemotor-like in appearance, having a conventional bicycle frame. The engine was mounted ahead of the bottom bracket and a V-belt from the engine drove a pulley clipped to the spokes of the rear wheel. The Mini Free won popularity, it became the best selling cyclemotor in Japan. It was sold at a uniform price of 23,000 yen across the whole country. Suzuki was producing 6,000 motorcycles per month in 1954 and changed its name to Suzuki Motor Co. Ltd in June 1954. The Mini Free was produced between 1954 and 1959. The specifications released by Suzuki reveal that the peak power of the engine increased from 1.8 hp (1.32 kW) to 2.0 hp (1.47 kW) in 1957. The dry weight of the engine also increased from 6.0 kg (13.2 lbs) to 6.5 kg (14.3 lbs). The latest Mini Free model was called MF5. It continued in production until 1959 and a more conventional moped, the "Suzumoped" replaced it. I'm still looking for information and pictures of the different versions of the bike and the engine.

Part of a Mini Free brochure, I found the image on the Internet.

An old Mini Free, spotted on the Japanese Yahoo Auction site in May 2006. Click to enlarge. The person who was selling this rarity announced that although the engine wasn't running, the crank was turning and there's spark on the plug. The fly wheel cover was missing, the tyres flat and most of the bike, obviously, quite rusty; but the inside of the fuel tank was clean.

Two more pictures of the same bike . Click to enlarge. It's hard to identify the model year for these early SJK/Suzukis. Different frames were used and details vary between individual bikes. The changes are pretty good that some of the original parts have been replaced or have disappeared after decades of use, although this one seems to be pretty stock. Note the speedometer and the headlight on the right picture - quite charming, aren't they? My guess is that the saddle comes from another bike but that doesn't surprise anyone. After all, these bikes were meant to be used at daily bases and most of them probably were. They haven't always been rarities. If somebody can tell what year this bike was made, please tell us all! You can find my e-mail address on the mail page.

1954 SJK Mini Free MF1 An early moped with a 50 cc two-stroke engine and belt drive. The SJK on the engine and the gas tank stood for Suzuki Jidosha Kogyo. Engine: Air-Cooled 50cc single cylinder two-stroke, 1.8 hp (1.32 kW) @ 4 500 rpm Click the image for larger format.

1954 SJK Mini Free MF1 Bore/Stroke: 38x44mm Compression ratio 7:1 Ignition: Flywheel magnet Clutch: Dry/Multi type Engine weight: 6 kg (13.2 lbs) Fuel consumption: 70 km/liter Max Speed: 45 kph Click the image for larger format.

Here's another Mini Free. Click the image for larger format.

1957 Suzuki Mini Free MF3 2.0 hp (1.47 kW) @ 4 500 rpm Do you know anything about these later MF models? Do you have better pictures? Brochure scans? Magazine adverts? Click the image for larger format.

1954–1959 SJK Mini Free specifications (Japan) Model: MF1–MF5 Engine: Air-cooled 50 cc 1-cylinder 2-stroke Peak power (1954–1956): 1.8 hp (1.32 kW) @ 4 500 rpm Peak power (1957–1959): 2.0 hp (1.47 kW) @ 4 500 rpm Maximum torque: N/K Fuel consumption: 70 km/liter Top Speed: 45 km/h (28 mph) Bore x stroke: 38 x 44 mm (1.496 x 1.732 in) Compression ratio: 7.0 Carburetor: N/K Engine weight (1954–1956): 6.0 kg (13.2 lbs) Engine weight (1957–1959): 6.5 kg (14.3 lbs) Starting method: Pedal Ignition system: Flywheel magnet ignition Fuel/lubricant mixture: pre-mix Lubricating oil capacity: 1.0 liter Fuel tank capacity 1954–1955: 2.0 liter Fuel tank capacity 1956: 2.7 liter Fuel tank capacity 1957: 3.0 liter Fuel tank capacity 1958–1959: 2.6 liter Clutch type: Dry multi-plate Gear ratios: — Primary reduction ratio: Gear drive Secondary reduction ratio: V-belt drive Retail price in Japan (1954): 23,000 yen Retail price in Japan (1958): 23,500 yen

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