BMW Motorrad R 1250 R Rider's Manual page 175

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and engine smoothness. As
well as adapting valve timing,
the partial-load cam also
reduces intake-valve lift. With
the partial-load cams activated,
moreover, the lobes for the
cylinder's left and right intake
valves produce staggered
valve lift and offset angles of
rotation. Consequently the
two intake valves open at very
slightly different times and the
distance to which they open
also differs. The advantage:
The fuel/air mixture flowing
into the combustion chamber is
swirled more thoroughly and
combusted effectively - so all
in all the fuel is utilised more
efficiently and engine operation
is perceptibly smoother. The
full-load cam is designed for
optimised engine power and
it maximises intake valve lift.
The intake camshaft is shifted
axially to vary valve timing
and valve lift. The pins of an
electromechanical actuator
engage a shift gate on the
intake camshaft. This permits
load-dependent and speed-
dependent actuation of the
intake valves and, consequently,
a no-compromises combination
of performance and low fuel
consumption.