BMW R27 Technical data
| Engine | |
| Operating priciple | Four-stroke cycle, valves overhead in V-arrangement |
| Maximum brake horsepower | 18 HP at 7400 rpm. |
| Number of cylinders | 1 |
| Cylinder Arrangement | Vertical |
| Bore | 68 mm. (2.677'') |
| Stroke | 68 mm. (2.677'') |
| Cylinder capacity | 245 c.c. (14.95 cu. in.) |
| Compression ratio | 8.2 : 1 |
| Valve timing with 2mm valve clearance |
|
Intake opens |
4º BUDC |
Intake closes |
23º ABDC |
Exhaust opens |
43º BBDC |
Exhaust closes |
16º BUDC |
| Valve clearance with engine cold (Running clearance): |
|
Intake |
0.15 mm. (.006'') |
Exhaust |
0.20 mm. (.008'') |
| Lubrication system | Pressure & Splash lubrication through gear-type
pump, oil sump in bottom of engine housing |
Carburetor |
|
| Design | Throttle slide carburetor with needle jet |
| Model | Bing 1/26/79 |
| Venturi | 26 mm. |
| Main jet | 120 |
| Needle jet | 45-291/1408 |
| Jet needle | 46-255 |
| Needle adjustement | 2 from above |
| Idle jet | 35 |
| Pilot air screw opened | 2 turns |
| Throttle slide | 22-540 |
| Weight of float | 11 grams (.388 oz.) |
| Carburetor air filter | Micronic dry filter |
Electrical equipement |
|
| Generator | Bosch LJ/CJE 60/6/1800 R 5 |
| Voltage regulator | Bosch RS/ZBS 45-60 6/1 |
| Ignition coil | Bosch TJ 6/1 |
| Spark plug | Bosch W 240 T 1, Beru 240/14 or Champion L 85; Electrode gap 0.6 mm. (.0236'') |
| Electric horn | Bosch HF 6 |
| Battery | 6 volts / 9 Ah. |
| Ignition system | Battery ignition with automatic timing by centrifugal advance unit |
| Contact breaker gap | 0.4 mm. (.0157'') |
| Initial ignition timing | 7º BUDC (Governor weights in initial position) |
| Maximum advance | 42º BUDC (Gocernor weights fully spread out) |
Lamp bulb data |
|
| Headlamp (High beam and Low beam) |
6 V, 35/35 W, bilux lamp |
| Pilot lamp (Parking lamp) | 6 V, 2 W, indicator lamp |
| Neutral indicator light | 6 V, 2 W, indicator lamp |
| Charge indicator lamp | 6 V, 2 W, indicator lamp |
| Speedometer dial light | 6 V, 0.6 or 1.2 W, indicator lamp |
| Tail and Stop light | 6 V, 5/18 W, twin-filament lamp |
| License plate light | 6 V, 5 W, spherical lamp |
| Directional signal light | 6 V, 18 W, strip lamp |
Power Train |
|
| Clutch | Single plate dry disc clutch with disc spring |
| Transmission | Four-speed type with sliding dog units, housing
bolted to engine. Torsional vibration damping through resilient drive shaft |
| Gearshift | Positive-stop foot control |
| Gear ratios: | In transmission |
First |
5.33 : 1 |
Second |
3.02 : 1 |
Third |
2.04 : 1 |
Fourth |
1.54 : 1 |
| Torque tranferring from transmission to rear wheel |
Cardan shaft drive totally enclosed within the rear, right-hand swinging arm, with elastic coupling and helical bevel gears in oil-tight housing |
| Bevel gear ratios: | |
Solo |
4.5 : 1 = number of teeth 27/6 |
Side-car |
5.20 : 1 = number of teeth 26/5 |
Chassis |
|
| Frame | Double tube steel frame |
| Front suspension | Bottom link swing fork with telecopic suspension
units and double-acting oil damping |
| Rear suspension | Swinging arm suspension with telescopic shock
absorbers and bouble-action oil damping |
| Brakes: | Front and rear-wheel internal shoe brake |
Brake drum diameter |
160 mm. (6.3'') |
Width of brake lining |
35 mm. (1.378'') |
Braking area |
194 sq. cm. (30.07 sq. in.) |
| Rims | Steel drop-center rims 2.15 B x 18 (36 spokes) |
| Tires | 3.25-18 |
Dimensions: |
|
| Overall width solo | 660 mm. (25.6'') |
with BMW side-car |
1520 mm. (59.8'') |
| Overall lenght solo | 2090 mm. (82.5'') |
with BMW side-car |
2300 mm. (90.5'') |
| Overall height | 975 mm. (38.4'') |
| Wheel base solo | 1380 mm. (54.3'') |
with BMW side-car |
1405 mm. (55.2'') |
| Track (Tread) BMW combination | 1090 mm. (42.9'') |
| Saddle height | 770 mm. (30.2'') |
| Ground clearance | 115 mm. (4.5'') |
Weights: |
Solo |
With Side-car |
| Curb weight*) | 162 kg. (356 lbs.) | 240 kg. (529 lbs.) |
| Allowable total weight**) | 325 kg. (716 lbs.) | 480 kg. (1058 lbs.) |
| Allowable wheel load, front | 120 kg. (264 lbs.) | 150 kg. (330 lbs.) |
| Allowable wheel load, rear | 210 kg. (463 lbs.) | 240 kg. (529 lbs) |
| Allowable wheel load, side-car wheel |
---- | 120 kg. (264 lbs.) |
| Maximum occupation including rider |
2 people | 3 people |
*) Curb weight = weight of motorcycle supplied with oil, fuel
and tools
**)Allowable total weight = Curb weight + people and luggage load
| Maximum recommended speeds |
Depend on the air resistance encountered according to size, position and clothing of rider |
| with run-in engine in km/h (miles/hour) | First |
Second |
Third |
Fourth |
| Solo | 35 (21) |
65 (40) |
95 (59) |
120 (74) |
| With side-car | 25 (15) |
50 (37) |
75 (46) |
90 (56) |
Fuel and lubricants |
||
| Fuel | Regular brand-name | gasoline |
| Lubricants | Engine: | Brand name HD oils for Otto-cycle engines. |
| For winter and transition periods: Multi-grade oil
SAE 10 W 30 For summer months single-grade oil SAE 30 For sustained sporty driving or at very high temperatures SAE 40 |
||
| Transmission: | Brand name HD oils for Otto-cycle engines SAE 10 W 30 | |
| Rear wheel drive: | Brand name HD engine oil SAE 40 | |
| Contact breaker lubricating felt: |
Bosch Ft 1v4 grease | |
| Bearing bushing for centrifugal advance unit: |
Bosch Ft 1v4 grease | |
| Wheel hubs and other lubrication points: |
Brand name "Multi.purpose" grease with a
melting point of 180ºC (356ºF) |
| Capacity of fuel tank | 15 liters (3.3 Imp. gal. or 4 U.S. gal.) |
| with reserve fuel supply of | 1.5 liters (sufficent for 40 km or 25 miles) |
| Oil capacity, engine | 1.25 liters (2.2 Imp. pints or 2.6 U.S. pints) |
| Oil capacity, gearbox | 0.65 liters (1.1 Imp. pints or 1.3 U.S. pints) |
| Oil capacity, bevel drive | 125 cc (1/4 U.S. pint) |
| Fuel cossumption according to DIN 70030: |
3.9 liters at 90 km/h or 72 m./Imp. gal. or 60 m./U.S. gal. at 56 mph. |
| Oil consumption | approx. 0.5-1.0 liters/1000km or 2820-5650
m./Imp.gal. or 2350-4700 m./U.S. gal. |