P94
FEATURE I PROTON KR3
carbs were meant to obviate
these difficulties.
All of these were undermined
by a single basic problem—ru-
inous vibration. "There was a
decision made early on that it
wouldn't have a balance shaft, so
the vibration level was quite high.
We went back to conventional
carburetors and radiator position,
but without a balance shaft… you
can't retro-fit one."
"I summed up the problems in
that year's Motocourse—"vibration
so severe that it snapped footrest
hangers, frothed the fuel and the
coolant, chafed through wiring,
caused component failures and
in general subjected the bike and
its riders to a constant destruction
test." Roberts blamed a mislead-
ing promise of greater stiffness
from the crankshaft manufacturer.
Clearly, a redesign was re-
quired. It came with a surprising
degree of help and cooperation
from the Japanese rivals, largely
(explains O'Kane) because of the
friendship and respect for Kenny.
There were three key figures—
the chief of Keihin Carburetors
Mr. Ito, HRC director Yoichi
Oguma, and Yamaha's "Mike"
Maekawa.
The Mk2 machine didn't appear
until the latter half of 1998, and
reversed the layout, with two cylin-
ders up and one down. It also had
a balance-shaft and was essen-
tially designed and built in Japan.
O'Kane explains: "The parts
were made by specialized
engineering companies with
experience supplying the exist-
ing teams. So, there was quite a
crossover, and they were compa-
nies we would never have access
to without Kenny being Kenny."
This help for rivals, continued
O'Kane, was not unusual, "for,
let's say, small operations. We'd
supported the Patons back in
the Yamaha days; Yamaha were
likewise very generous with their
resources and their advice when
Cagiva were being developed.
"The paddock is a family, and
nobody wants to see anybody
being humiliated. It's a very Japa-
nese thing."
The second engine eliminated
the vibration with a balance shaft.
But this brought its own prob-
lems. "It was basically quite long.
The layout of the shafts was like
This excellent video was created
four years ago in South Africa and
details the restoration of Nobu
Aoki's 2003 KR3 by former racer
Rory Nisbit and features riding from
current MotoAmerica Superbike
rider Cameron Petersen's father,
former AMA star Robbie Petersen.
