Dirt & Trail Aug2020

electric start engine features an
all-new cylinder head with an
improved intake port shape and
new camshaft profile.
There is a new air box
and intake track, silencer
and an updated ECU. These
modifications, along with an
updated transmission and shift
cam, revised clutch design and
improved water pump impeller
produce a more competent
machine.
The lightweight aluminium,
bilateral beam frame has
redesigned engine mounts with
better flex characteristics.
The Kayaba SSS forks have
enhanced speed-sensitive
damping, while the Kayaba shock
gets revised damping.
Top triple clamp, handlebar
mounts and front axle are
redesigned to compliment the new
frame.
Improved braking performance
is achieved with lighter weight
front and rear brake calipers,
larger brake pads and redesigned
270mm front and 240mm rear
rotors.
Standard equipment includes
electric start, lithium battery, fuel
injection, downdraft intake tract
and rear-exit exhaust layout.
Racers can adjust ECU straight
from their phone using the on
board Wi-Fi Yamaha Power Tuner
App.
What’s new for the 2021
YZ450F?
Compact 450cc 4-valve engine. The
rearward-slanted cylinder gives
mass centralized design. Reversed
cylinder head with forward-facing
inlet and rear-exit exhaust.
Yamaha Power Tuner for instant
trackside tuning via a smartphone.
2-mode handlebar button for
switching engine power map while
riding.
Compact electric starter with
ultra-light battery.
Launch Control System (LCS)
optimizes engine output for
quicker starts.
Agile and lightweight aluminium
bilateral beam frame.
Slimline body and seat.
KYB coil spring-type speed
sensitive front suspension. Linktype
Monocross rear suspension
with specially-tuned KYB shock.
Lightweight wheels with blue
rims.
270mm front disc, 240mm
rear disc. 4-position adjustable
rubber-mounted handlebar clamp.
Tapered aluminium handlebars
with quick-adjust clutch perch.
The 2-Strokes:
With their liquid-cooled 2-stroke
engines and high-specification chassis
designs, the YZ65 and YZ85 give youth
racers a great start into motocross
with the YZ125 perfect for teenagers to
sharpen their race skills before moving
up to the adult category.
Yamaha’s YZ250 2-stroke motocross
bike has a loyal following of committed
racers and leisure riders all over the
world.
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