VOL. 52 ISSUE 6 FEBRUARY 10, 2015 P79
snake. And somewhere in the
middle was the new YZF-R1.
This was the biggest over-
haul of the bike yet and owed
almost nothing to R1s of the
past. The engine was a new
short-stroke, ram air-assisted
design that saw power reach
a claimed 180hp under full
load. In fact this YZF-R1 was
the first production machine to
claim the magic 1:1 power to
weight figure of 172 hp and 172
kg (379-pounds). In reality this
wasn't strictly true, as Japa-
nese manufacturers still quoted
dry weights back then. With a
tank of fuel, ready to ride you
were looking at around 205 kg
(451-pounds).
But back to the good stuff.
As mentioned, the engine
was an all-new short stroke
unit with dimensions of 70 x
53.6mm bore and stroke. Ya-
maha chose this design to get
more power higher in the rev
range–indeed peak power was
now claimed to be 2000 rpm
higher than before at 12,500
rpm. Ram-air was also a first
for the YZF-R1 and controlled
by a set of secondary throttle
valves. This was not the YCC-
T/YCC-I system, mind you.
That came a couple of years
later.
The compression ratio on
the 2004 YZF-R1 was bumped
up to 12.4:1 and the cylinders
were angled at 40-degrees to
allow the new chassis to be
narrower. This was also the
first time the engine wasn't
used as a stressed member
of the chassis, meaning the
cylinders could now be bolted
instead of cast onto the crank-
case.
Yamaha's own MotoGP pro-
gram heavily influenced the de-
sign of the 2004 YZF-R1, with
the chassis dimensions closely
mimicking those of the racer
and with the engine no longer
a stressed member, the chas-
sis was 64mm narrower than
before. The roadbike also got
the upside-down truss layout
swingarm design and radially-
mounted brake calipers and
master-cylinder. New, lighter
five-spoke alloy wheels com-
pleted the chassis changes.
Easily the most striking ele-
ment of the new machine was
"THE BUM WAS JUST AS NICE AS THE
FACE, WITH THE ALL-NEW UNDERSEAT
EXHAUST SYSTEM STICKING OUT THE
BACK AND CREATING ONE OF THE MOST
RECOGNIZABLE FEATURES ON THE
MARKET AT THE TIME."
