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Evolution of the Species
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Evoluzione Cyclesports BMW K 1200 S
Jeff Buchanan
11/01/2006
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Photography by Kevin Wing
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Building an engine solely to produce the highest
possible peak power tends to result in a redline frame of mind that may work on
a racetrack, but is somewhat futile in a street bike. The ZTechnik pipe created
the best result throughout the powerband, boosting mid-range (at about 5,000
rpm) and adding a full seven to eight horsepower at the K bike’s redline of
10,500 rpm. The ZTechnik pipe, with its short muffler, looks truly aggressive
and emits a crisp exhaust rasp. The full-length titanium system, held in place
by an Evoluzione exhaust hanger, is signficantly lighter than the stock
assembly.
 The blue-and-orange Evoluzione Sportscycles BMW R 1200 S induces double-yellow
fever. (Click image to enlarge)
The next obvious place to look for more performance was the
airbox. Incoming air had to navigate noise-reducing snorkels that funneled it
through an inefficient, circuitous route before it met the combustion process.
The Evoluzione “race airflow system” reduces the pumping losses of the stock
intake system, resulting in a five to six horsepower gain.
But, perhaps the
most in-depth modification for the Evoluzione K bike was reshaping the head.
Zeller and his team were impressed with the stock head design, thus they were
initially unsure how to improve upon it. However, after some full-flow bench
testing, they were able to increase flow by roughly 12 percent, picking up an
astounding nine additional horsepower. (Evoluzione will have a Stage 2 head
available soon, which is expected to bump power at least 10 horses over
stock.)
Top: The K 1200 S is an adept sprinter. Bottom: The R GS 1200
begs for
long-distance adventures. (Click images to
enlarge)
An Italian-made Dimsport Rapidbike on-board electronic control box
was added, allowing fuel curve and spark advance adjustments to be made,
complementing the new engine modifications; and then Zeller rolled the
Evoluzione K 1200 S onto the dyno. The machine produced an astonishing 190 hp at
the crankshaft (an increase of 23 hp over stock), and torque had been boosted
from 93 ft lbs to 102, giving the bike more pulling power.
The bottom end of
the engine was left stock, save an Evoluzione clutch slave cylinder. Milled from
billet aluminum, it utilizes a larger, diameter piston that reduces lever
effort approximately 20 percent, making for smoother, easier clutch action. An
Evoluzione needle-bearing shift lever and linkage is partnered to a quickshifter
that works with the DimSport Rapidbike for clutchless up-shifts under power. The
linkage is reversible to accommodate a traditional race shift pattern for the
track, if desired.
For the time being, the K 1200’s suspension has been left
alone. The exclusive BMW Duolever front end and EVO Paralever rear end deliver a
stable ride and, by utilizing the Electronic Suspension Adjustment, the
suspension can be set for aggressive riding by simply choosing the two-up,
with baggage setting for added stiffness and adjusted to the sport level for
appropriate response.
 The K 1200 S is a long motorcycle and, although it
turns-in remarkably well, Zeller felt there was room for improvement. Fabricated
from billet aluminum, an entirely new, adjustable torque arm was allows for
changes in ride height to suit individual rider preference. The unit was
adjusted to 15mm longer than stock, resulting in an increase of 8mm to rear ride
height, which translates to a quicker, more precise turn-in. For lengthening or
shortening, the arm uses shims to avoid the stress loads being absorbed by
threads. (Click image to enlarge)
Embellishing the K’s already roomy cockpit, new brackets were
created to lower the footpegs one full inch and pull them back slightly,
resulting in an even more spread out, comfortable leg/knee bend for the rider.
The lower pegs take away some of the available lean angle and aggressive riding
can result in touching down. However, for most instances, there is plenty of
clearance. Zeller is experimenting with a quick-change footpeg, that, without
the need of tools, can be raised or lowered—as well as flipped over for a choice
of peg surfaces—to suit various riding situations.
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