Junak WB1/WB3 (1959-65)

The Junak WB1/WB3 was a motorbike produced from 1959-65, totaling 8500 units. It was powered by a four-stroke, single-cylinder, OHV engine with a capacity of 349 cc and a compression ratio of 7.0:1. The bike was air/oil-cooled and lubricated by dry-sump. It had a max power of 14 kW / 19 hp at 6000 rpm and a max torque of 27.5 Nm / 2.8 kgf-m / 20.3 ft-lb at 3800 rpm, with a top speed of 85 km/h / 52.8 mph. The Clutch was a multi-plate clutch with cork inserts working in an oil bath, and the dynamo was 45 W. The transmission was four-speed constant-mesh, and the final drive was a chain. The frame was double cradle type, telescopic front shock absorbers, and independent rear wheel suspension. The brakes were full hub width of expander shoe type with hand and foot operating. The wheels were interchangeable wire type with quick-detachable spindles, and the front and rear wheels had a rim of 89 mm / 3.5 in. The bike had an overall length of 2195 mm / 86.4 in, width of 1490 mm / 58.7 in and a height of 1120 mm / 44.1 in. Additionally, it came with a sidecar that had dimensions of 1800 mm / 70.9 in in length and 1120 mm / 44.1 in in height. The wet weight of the bike (including the sidecar) was 260 kg / 573.2 lbs, and the load capacity was 210 kg / 463 lbs. The fuel capacity was 17 l / 3.9 US gal, and the average consumption was 5.7 l/100 km / 17.5 km/l / 41.3 mpg.

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Technical specifications:

Make Model: Junak WB1/WB3

Year: 1959 – 65

Production: 8500

Engine: Four stroke, single cylinder, OHV

Capacity: 349 cc / 21.3 cub. in.

Bore x Stroke: 75 x 79 mm

Compression Ratio: 7.0:1

Cooling: Air/Oil cooled

Lubrication: Dry-sump

Ignition: Magneto

Battery: 14 Ah, 6V

Dynamo: 45 W

Starting: Kick-start

Clutch: Multi-plate clutch with cork inserts working in an oil bath

Max Power: 14 kW / 19 hp @ 6000 rpm

Max Torque: 27.5 Nm / 2.8 kgf-m / 20.3 ft-lb @3800 rpm

Transmission: Four-speed constant-mesh

Final Drive: Chain

Gear ratios: 1st 3.04 / 2nd 1.97 / 3rd 1.29 / 4th 1.00:1

Frame: Double, cradle-type, welded throughout of tubing, provided with holders for side car mounting.

Front Suspension: Fork with coil springs telescopic shock absorbers

Rear Suspension: Independent rear wheel suspension on single wishbone , cooperating with 7- leaf spring positioned transversely;

Front Brakes: Full hub width, of expander shoe type, hand operated

Rear Brakes: Full hub width, of expander shoe type, foot operated

Wheels: Wire type, with full width hubs made of light alloy, interchangeable (also with side-car wheel). Both wheels with quick-detachable spindles

Front Tyre: 19 in

Rear Tyre: 12 in

Front Rim: 89 mm / 3.5 in

Rear Rim: 89 mm / 3.5 in

Trail: 72 mm / 2.8 in

Overall Dimensions: Length: 2195 mm / 86.4 in Width: 1490 mm / 58.7 in Height: 1120 mm / 44.1 in

Dimensions of Sidecar: Length: 1800 mm / 70.9 in Height: 1120 mm / 44.1 in

Rear Track: 1020 mm / 40.2 in.

Wheel Base: 2010 mm / 79 in

Seat Height: 755 mm / 29.7 in

Ground Clearance: 170 mm / 6.7 in

Wet Weight (incl sidecar): 260 kg / 573.2 lbs

Weight of Sidecar: 67 kg / 147.7 lbs

Load Capacity: 210 kg / 463 lbs

Fuel Capacity: 17 l / 3.9 US gal

Average Consumption: 5.7 l/100 km / 17.5 km/l / 41.3 mpg

Top Speed: 85 km/h / 52.8 mph

Source: Article by T. Tomaszewski in ‘Swiat motocykli 2003.