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BMW K 75S

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Make Model

BMW K75S

Year

1987 - 89

Engine

Four-stroke, horizontal three cylinder in-line, DOHC, 2 valves per cylinder

Capacity

740 cc / 45 cub-in
Bore x Stroke 67 x 70 mm
Compression Ratio 11.0:1
Cooling Liquid cooled
Lubrication Wet sump

Induction

Electronic injection, Bosch LE-Jetronic

Starting

Electric

Max Power

55 kW / 75 hp @ 8500 rpm

Max Torque

68 Nm / 50 ft lb @ 6750 rpm

Transmission

5 Speed

Clutch

Single dry plate
Final Drive Shaft
Gear Ratios 1st 4.50 / 2nd 2.96 / 3rd 2.30 / 4th 1.88 / 5th 1.67:1
Frame Double-downtube frame with engine as a stressed member; box-section aluminum monolever swing arm

Front Suspension

Telescopic fork with hydraulic shock absorber

Front Wheel Travel

185mm / 7.3 in

Rear Suspension

Monolever swinging arm

Rear Wheel Travel

114mm / 4.5 in

Front Brakes

2 x 285mm discs, 2 piston calipers

Rear Brakes

Single 285mm disc

Front Tyre

100/90-18

Rear Tyre

130/90-17

Dimensions

Length 2220 mm / 87.4 in
Width    900 mm / 35.4 in
Height 1340 mm / 51.2 in
Wheel Base 1516 mm / 59.7 in
Seat Height 810 mm / 31.9 in or 760 mm / 29.9 in. for low seat model
Ground Clearance 175 mm / 6.9 in

Dry Weight

229 kg / 505 lbs

Wet Weight

235 kg / 518 lbs

Fuel Capacity 

21 Litres / 5.54 US gal

Fuel consumption

4 l/100 km / 25 km/l / 59 US mpg

Acceleration 0 - 100 km/h / 62 mph

4.7 sec

Top Speed

210 km/h / 131 mph
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The K75S is a small bike using the contemporary engine technology, aimed at sportier riders, and not caring much about full-on touring. It has a number of sportier features than other bikes in the line, without giving up the basic refinement and style of those bikes.

Since the K-bike line was intended to replace the Boxers entirely at the time this motorcycle was being designed, this makes sense as an R65 LS replacement.

The engine is a three-cylinder inline engine, much like a shrunk-down car engine. It uses fuel injection instead of carburetion. From the clutch to the drive shaft is basically unchanged -- still a single plate clutch and nearly the same clunky gearbox. The brakes in front are remarkably similar to the R65 LS's, but the back is a much better disc brake. The frame is significantly different from the R65, with the engine forming a member of the frame, rather than resting inside it.

Review:

The K75S uses the same running gear as the K75 - same frame, same shock and made-for-BMW Shown fork, same engine, transmission and tires - but with low, narrow bars and fairing to give it a sport-touring look.

The K75S works well enough, and feels as solid as a Bavarian boulder, but is let down by a soft engine and by paint which for this price (nearly $9000) should be as smooth as Alpine ice, but instead has a surface more like the skin of a Portuguese orange. What it does have, though, is a scat by Corbin, handlebar switchgear that is quite unlike anybody else's and which works very well indeed, excellent brake feel and the ability to haul you and a passenger comfortably and securely for long distances, at a moderate-to-quick sport-touring pace, without half trying.


The three-cylinder motor is tuned for smoothness and midrange oomph, and while it isn't exactly, well, slow, hard-core performance-types probably won't be satisfied with it, though the fuel injection system gives it very good throttle response. On curvy roads, it just doesn't make enough power to keep up with most of the rest of this gang. That's as well, probably, because the bike's rear shock isn't up to fast paces, especially over bumpy roads. Work it hard over such surfaces and it'll soon will, letting the bike wallow.

Do we hear you muttering, "But this isn't a sportbike?" You're right. It's a civilized, low-pressure sport-tourer, and as such, gives a good account of itself.