that feature a single-core design rather
than a two-core design. The height of the
radiators has been lowered 20mm and the
thickness reduced 10mm, and they are
interchangeable between the two bikes.
For the 2S0F, the new radiator means a 21percent increase in surface area, while it
remains the same for the 4S0.
Both bikes also get new kickstart levers
that feature more footpeg clearance and
more rib area for your boot to grip.
As for individual changes, the YZ2S0F's
oil tank has been repositioned to the lower
front of the frame and is protected by the
skid plate.
The crankcase has been redesigned to
increase space at the oil pickup, and an oil
check window has been added.
The 2S0F's muffler carries 7 percent
more packing and features a new, more
eye-pleasing end cap (as does the 4S0).
The rest of the exhaust pipe is all new and
is said to improve midrange performance.
Internally, the 2S0F also gets different
ignition mapping and carburetor settings.
Pretty much everything about the
4S0F's five-valve, DOHC engine is new. It
has a new cylinder-head design, a new
exhaust pipe and silencer, a new crankshaft, a new counter-balancer, and a new
dry-sump lubrication system. The cylinder
incline has also been changed 4 degrees,
leaning toward the center of the bike for
better CG purposes.
Other engine changes include a
reshaped cylinder intake port and bolts
that are now used in place of studs and
nuts on the cylinder head.
As far as the YZ2S0's individual changes,
it really didn't get any other than the previously mentioned, across-the-board mods
that all of the yz. got. Yamaha felt no need
to make any changes to the YZ2S0's
motor.
The YZI2S, however, did get a few
motor updates to give it more power. It
gets a new cylinder head, carburetor
mods, new YPVS power-valve and ignition
mapping settings, and a new platinum
spark plug.
As for the Yamaha YZ8S, it sees no
changes for '06.
To celebrate Yamaha's SOth anniversary,
it will be offering special edition YZ2S0 and
YZ450R
Special Edition
4S0Fs in a yellow and black color scheme
to commemorate the yz. of the I970s and
early '80s. The SEs will cost about $200
more than the standard blue yz..
Unfortunately, it's going to be awhile
before you see the new four-strokes on
your dealer's showroom Ooor. The '06
~SOF isn't slated to be released until late
September, the YZ4S0F early November.
The two-stroke should be released around
eN
midsummer.
MSRP
VZ8S
VZ 125
VZ2S0
VZ250F
VZ250F SE
VZ450F
VZ4S0F SE
$3099
$5499
$6199
$5999
$6199
$6899
$7099
CYCLE NEWS • JULY 20, 2005
43
