BMW AG Presse - BM Bikes, BMW Motorcycle Information

BMW AG Presse
Increase in engine size
The first and most important step in creating the right kind of power base was
to increase engine capacity, especially as the engine of a real cruiser can
never be too large. So enlarging bore from 99 to 101 mm (3.90 - 3.98"), and
extending stroke from 70.5 to 73 mm (2.78 2.87"), the Motorcycle Division's
engine specialists were able to beef up the original power unit from 1085 cc to
1170 cc for the BMW
R 1200 C, in the process creating the largest BMW motorcycle engine ever
built.
The torque curve - like the back of a buffalo
The obvious result of this exercise is that the engine now develops even more
thrust with even greater superiority - but even that was not enough for
BMW's specialists in establishing their own specific definition of the optimum
cruiser. Rather, they also wanted to dedicate a kind of monument to this hightorque
power unit, giving it a torque curve which, by way of analogy, follows
the profile of a buffalo back. And the result is a power unit so independent of
high engine speeds that it does not even require a rev counter.
Minor modifications in further support of the cruiser concept
BMW's engineers have succeeded in changing the fundamental character of
the Boxer engine by introducing a whole range of small but important
modifications, without changing the fundamental configuration of the fourvalve
Boxer engine in the process.
Among others, the following modifications are worth noting in this context:
- Reduction in valve diameter
(intake valves 34 mm (1.34"), outlet valves 29 mm (1.14") on the R 1200
C as opposed to 36 mm (1.42") and, respectively, 31 mm (1.22") on the R
1100 RS)
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