BMW K 1300 GT - Manual (Page 74)

BMW
Media
Information
10/2008
Page 74
Back in 1983, when many motorcycle manufacturers still placed their bets on
inline engines with air cooling, liquid-cooled four-cylinder power units marked
the highest level of technology in motorcycle construction. But instead of
resorting to the usual engine layouts, BMW engineers Josef Fritzenwenger
and Stefan Pachernegg succeeded in developing a brand-new future-oriented
technical concept subsequently enhanced all the way to regular production
quality.
In the process they maintained the longitudinal position of the crankshaft
typical up to that time of BMW motorcycles with a direct fl ow of power from
the gearbox through the drive shaft to the rear wheel, referred to under
the offi cial term as the BMW Compact Drive System. A brand-new approach,
on the other hand, was the introduction of liquid cooling.
Displacing 987 cc, the straight-four power unit is fi tted in longitudinal, fl at
confi guration. The crankshaft is on the right-hand side seen in the direction
of travel, while the cylinder head with the two overhead camshaft is on the left.
Liquid cooling comes for the fi rst time on this new BMW, ensuring not only
supreme thermal stability, but also, through effi cient soundproofi ng, a very low
level of mechanical noise.
Two other innovations likewise characterised the new engine: First, electronic
fuel injection supplying fuel to the combustion chambers. Second, the
layout of the engine as a load-bearing element fully integrated in the light and
torsionally stiff tubular steel spaceframe.
This principle sets the foundation for the BMW K-Series motorcycles. So
regardless of whether they are Sports Machines, Tourers or Naked Bikes –
the K-Series proves to be extremely innovative and versatile in technical terms
and virtually every other respect. To this day, the concept of the straight-four
fi tted lengthwise remains within the BMW Motorrad model range in the guise
of the K 1200 LT Luxury Tourer.
Ongoing development of the K-Series also provides important momentum
for a brand-new technical approach. In 2004, for example, the fi rst
BMW K Series with its four-cylinder engine fi tted crosswise sees the light
of day – the K 1200 S as the most powerful and fastest BMW of all times.
4. 25 Years of BMW K-Series.
4.1 The Inline-Engine BMW.