BMW R 42

BMW R 42 Date 1926-1928

Number sold 6.502

Price 1.510,- RM

Engine

internal designation M 43
engine type four-stroke two-cylinder flat-twin
bore x stroke 68 x 68 mm
displacement 494 cm3
output 12 PS at 3400 rpm
compression ratio 4,9 : 1
valves sv
carburetion system 1 carburettor BMW Spezial two-valve 22 mm
engine lubricating forced-feed lubrication
oil pump gear pump

 
Power transmission

Clutch single discs, dry
no. of gears 3
shifting manual
Gear ratios 2,49 / 1,50 / 1,08
rear wheel ratio 1 : 4,53 or 1 : 3,8 (sidecar 1 : 6, 27 or 1 : 5,7)
bevel/crown wheel 15 / 68 or 15 / 57 teeth (sidecar 11/ 69 or 10 / 57)

 
Electrical system

Alternator magneto generator on request
Ignition Bosch magneto ignition
Spark plugs Bosch W 175

 
Suspension

designation R 42
frame twin-loop steel tubular frame
front wheel suspension plate spring, 5 laminae
rear wheel suspension rigid
wheel rims deep-bed 19 x 3 or 21 x 2,5
tyres, front 26 x 3,5 on 19 x 3 or 27 x 2,75 on 21 x 2,5
tyres, rear 26 x 3,5 on 19 x 3 or 27 x 2,75 on 21 x 2,5
brakes, front drum brake 150 mm
Brakes rear external shoe brake at gearing (on cardan shaft)

 
Dimensions and weights

Length x width x height 2100 x 800 x 950 mm
Wheel base 1410 mm
Tank capacity 14 l
Unladen weight, full tank 126 kg (with Original sidecar 188 kg)
load rating k.A.
Fuel consumption ca. 3 l / 100 km
oil consumption ca. 1,7 l / 1000 km
Top speed 95 km/h