Junak WB1/WB3

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 „Świat motocykli” 2003.

Szczecin Motorcycle Factory developed and started to produce in 1959 a M07 with passenger side loader , branded as the WB1 and was later followed by the WB3. In essence these two motorcycles are the same - the WB1 is based on the M07 and the WB2 on the later model M10.

The frame of welded steel tubes suitable for four-point connection to the motorcycle, equipped with two ball joints and two tubular struts .

The sidecar, made of steel suspended for rotation in the front part of the frame and on the back of the two stretched rubber rings . Seat covered with vinyl, and was equipped with a reclining backrest , and housed a luggage bay . The sides were equipped with soft armrests. A sheet black canvas covered the sidecar.