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[[Image: | {{DISPLAYTITLE:{{PAGENAME}}: history, specs, pictures}} | ||
{{Infobox Motorcycle | |||
|name = '''BMW R 4''' | |||
|image = [[Image:R4.jpg|frameless|BMW R4]] | |||
|aka = | |||
|manufacturer = [[BMW]] | |||
|parent_company = | |||
|production = 1932 - 1937 | |||
|model_year = | |||
|predecessor = | |||
|successor = | |||
|class = [[Classic]] | |||
|engine = air-cooled, four-stroke, single vertical cylinder | |||
|bore_stroke = 83.8mm x 83.8mm | |||
|fuel_system = carburetor. sum ck 3/500 fr | |||
|compression = 5.7:1 | |||
|top_speed = 59 mph (95 km/h) | |||
|power = 13.95 HP (10.4 KW) @ 4000RPM | |||
|torque = | |||
|ignition = | |||
|spark_plug = | |||
|battery = | |||
|transmission = Gear box: 4-speed, manual <br> | |||
Final Drive: [[shaft]] <br> | |||
Clutch: dry, single plate <br> | |||
|frame = | |||
|suspension =Front: parallelogram fork <br> | |||
Rear: hard-tail, sprung seat | |||
|brakes =Front: 160mm drum <br>Rear: 160mm drum | |||
|front_tire = {{tire|3.50 x 26}} | |||
|rear_tire = {{tire|3.50 x 26}} | |||
|rake_trail = | |||
|wheelbase = | |||
|length = | |||
|width = | |||
|height = | |||
|seat_height = | |||
|dry_weight = | |||
|wet_weight = 137.0 kg | |||
|fuel_capacity = | |||
|oil_capacity = | |||
|fuel_consumption = 3.50 liters/100 km (28.6 km/l or 67.21 mpg) | |||
|turning_radius = | |||
|related = | |||
|competition = | |||
}} | |||
The '''[[BMW]] R4''' was a air-cooled, four-stroke, single vertical cylinder Classic [[motorcycle]] produced by [[BMW]] in 1932. Claimed [[horsepower]] was 13.95 HP (10.4 KW) @ 4000 RPM. | |||
[[Image:R4.jpg|thumb|350px|BMW R4]] | |||
[[BMW]] produced 15,200 '''R4''' [[motorcycles]] using innovative mass production techniques, setting new standards of design and quality. Pressed steel frame and components were quick and easy to stamp out and assemble, reducing manufacturing costs. | [[BMW]] produced 15,200 '''R4''' [[motorcycles]] using innovative mass production techniques, setting new standards of design and quality. Pressed steel frame and components were quick and easy to stamp out and assemble, reducing manufacturing costs. | ||
Introduced in 1932 and intended to bridge the gap between the 'budget' [[BMW R2|BMW R2]] 198cc single and the expensive twins, the R4 looked much like the former, whose channel-section steel frame and running gear it used almost unaltered. The 398cc overhead-valve engine featured enclosed valve gear and produced 12bhp, gaining an extra two horsepower in 1933 when the [[BMW|BMW]] R4 was updated to Series 2 specification with revised styling and a four-speed gearbox. A new cylinder head, tidier engine casings and changes to the toolbox and generator locations were introduced as the rugged R4 - a favourite with police forces and the German Army - progressed through to Series 5 before production ceased in 1936. | |||
==Engine== | |||
A 83.8mm [[bore]] x 83.8mm [[stroke]] result in a [[displacement]] of just 498.0 cubic centimeters. | |||
==Drive== | |||
The bike has a 4-speed, manual transmission. Power was moderated via the dry, single plate. | |||
==Chassis== | |||
It came with a 3.50 x 26 front [[tire]] and a 3.50 x 26 rear tire. Stopping was achieved via 160mm drum in the front and a 160mm drum in the rear. The front suspension was a parallelogram fork while the rear was equipped with a hard-tail, sprung seat. | |||
==1932 - 1937 BMW R 4== | |||
<gallery mode="slideshow"> | |||
File:bmw-r-4-1932-1937-3.jpg|600px|1932 - 1937 BMW R 4 | |||
File:bmw-r-4-1932-1937-2.jpg|600px|1932 - 1937 BMW R 4 | |||
File:bmw-r-4-1932-1937-1.jpg|600px|1932 - 1937 BMW R 4 | |||
File:bmw-r-4-1932-1937-0.jpg|600px|1932 - 1937 BMW R 4 | |||
</gallery> | |||
The 1932 BMW R 4 has, at its heart, an air-cooled, four-stroke, 498cc, single vertical cylinder engine mated to a four-speed manual transmission that can produce a claimed 14 horsepower at 4000 rpm. This classic machine had standard features such as laced wheels, full fenders, a hard-tail rear suspension with a sprung seat, a parallelogram front suspension, a large headlight, a rear luggage rack and an exhaust system with a large-diameter muffler. | |||
==In Media== | |||
* [https://motopixel.org/pixel/jeder-stirbt-fur-sich-allein#bmw-r-4 Jeder stirbt für sich allein] | |||
* [https://motopixel.org/pixel/roma-citta-aperta#bmw-r-4 Rome, Open City] | |||
{{BMW}} | {{BMW}} | ||
[[Category:Classic motorcycles]] | |||
[[Category:BMW motorcycles]] | [[Category:BMW motorcycles|R4]] | ||
[[Category:1930s motorcycles]] | |||
[[Category:BMW R series]] | |||
[[Category:1930s motorcycles]] |