VOL. 55 ISSUE 37 SEPTEMBER 18, 2018 P89
racetrack, which meant I had to
use the clutch when downshift-
ing under braking, the Triumph
stopped well thanks to the excel-
lent Nissin radial front brakes,
and a fair bit of engine braking
left dialed in to the slipper clutch
setup. Yet it was totally stable
driving hard through the only fast
third-gear turn on the Stowe cir-
cuit. Nice, but it left me thirsting
ened—but a close-
ratio six-speed
gearbox has been
created by fitting a
taller ratio first gear
and slightly shorter
second gear, while
retaining the same
upper four ratios in
the 765RS street
bike transmission.
It's worth noting that Moto2 teams aren't allowed
to change the internal ratios of the gearbox, nor
the primary drive, which is also standard on the
Triumph motor, but the race-developed slipper
clutch now fitted is tuneable.
The stock offset chain drive to the cams has
been retained, rather than gears, and the rev
ceiling's been raised from 12,650 rpm on the road
bike, to 14,000 rpm—an impressive demonstration
of the robustness of the 765 Street Triple engine.
"It's an engine that we know very well, because
the fundamentals of the design remain the same as
the Daytona 675 that came out in 2006," says Sar-
gent. "So, we do know the engine very well, and in
terms of understanding what we needed to do to it
to provide adequate performance, it meant doing
things that we pretty much knew already anyway."
The result delivers what Sargent confines him-
self to stating is "over 135 horsepower" at 14,000
rpm versus the street 765RS's 123 horsepower
at 11,700 revs, with 59 lb-ft of torque at 13,500
rpm versus 56.7 lb-ft at 10,800 rpm on the RS.
But whereas the 765RS figures are taken at the
crankshaft, Sargent declares the Moto2 readings
to be taken at the gearbox i.e. on a dyno (how-
ever, Chaz Davies' smaller capacity 675 Supers-
port revved as high as 15,500 rpm and produced
144 bhp at the rear wheel, so there's surely room
for development).
Davies' smaller capacity WorldSSP motor pumped out
a massive 144 hp in race trim, 14 hp more than what
Triumph is claiming for the Moto2 engine.
Keihin throttle bodies will
be exclusively used on the
Moto2 engine.
The standard crankshaft,
counterbalancer, conrods and cast
three-ring pistons are all retained in
unmodified form on the race engine.
