Suzuki 125 S31
1962—1963

I have tried to tell the history of the Suzuki 125 S31 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.

Suzuki presented the 125cc Sports S31 model in 1963. It was advertised as a casual sports model suitable for touring, commuting, and short trips. Its 125cc air-cooled two-cylinder engine, using a two-carburetor system, achieves a top speed of 115km/h and a maximum output of 12.5PS, and while it delivers high performance (at the time), it also achieves economical fuel efficiency of 60km/L (constant fuel consumption). The S31 had both electric and kick starter. The transmission was a rotary four-speed with a rational gear ratio, designed to be satisfactory under a variety of driving conditions. The front suspension was an modern and sporty oil-damped telescopic fork, to improve stability on rough roads, the same as a racer. The upswept exhaust pipes allowed the bike to lean further. The model was released to commemorate Mitsuo Ito's victory in the 1963 Isle of Man TT race, the first victory for a Japanese rider, and his continued victories in World GP races. The model was only manufactured during a brief period in 1962—1963. It was exported to USA where it was sold as S31 Collegian.

1963 Suzuki 125 S31, as shown in a '63 Suzuki sales catalog

1963 Suzuki Sport 125 S31 Overall Length: 1 930 mm (76.0 in) Overall Width: 675 mm (26.6 in) Overall Height: 932 mm (36.7 in) Wheelbase: 1 260 mm (49.6 in) Ground Clearance: 130 mm (5.1 in) Dry Weight: 120 kg (264 lbs) Engine: Air-cooled 124 cc 2-stroke inline twin. 12.5 hp (9.19 kW) @ 8 000 rpm, 11.8 Nm (1.2 kg-m) @ 6 000 rpm Click on the image for larger format.

1963 Suzuki Sports S31 specifications (Japan) Overall Length: 1 930 mm (76.0 in) Overall Width: 675 mm (26.6 in) Overall Height: 932 mm (36.7 in) Wheelbase: 1 260 mm (49.6 in) Ground Clearance: 130 mm (5.1 in) Dry Weight: 120 kg (264 lbs) Engine model: Engine: Air-cooled 124 cc parallel twin, 2-stroke Bore x stroke: 42 x 45 mm (1.654 x 1.772 in) Compression ratio: 7.0 : 1 Peak power: 12.5 hp (9.19 kW) @ 8 000 rpm Maximum torque: 11.8 Nm (1.2 kg-m) @ 6 000 rpm Claimed top speed: 115 km/h (71.5 mph) Carburetor: VM17SC x 2 Starting system: Electric and kick starter Ignition system: Battery Fuel/lubricant mixture: Pre-mix Lubricating oil capacity: — Fuel tank capacity: 8.0 liter (2.11 US gal. / 1.76 Imp gal.) Fuel consumption: 60 km/liter (at 40 km/h constant speed) Clutch type: Wet multi-plate, coil spring Transmission type: Constant mesh, 4 speeds return Gear ratios: 2.540 / 1.470 / 0.960 / 0.740 Primary reduction ratio: 2.540 Secondary reduction ratio: 1.560 Frame type: Pressed steel plate, backbone Caster: 28°00′ Trail: 73 mm (2.874 in) Brake type (front): Internal expansion, mechanical type Brake type (rear): Internal expansion, mechanical type Front tyre: 3.00-16-4PR Rear tyre: 3.00-16-4PR Recommended retail price in Japan: 143,000 yen

More: All Suzuki models

This free site is managed by Jarmo Haapamäki.
If you find this site helpful, please leave a donation for Jarmo
so you can enjoy the spirit of giving too.

Came here from a search engine?
Click at the home button below to get to the main page with frames.