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Printable Version |
Dirt Bike
Magazine: 2004 YZ250F
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The only five-valve game in town
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| lt lost 6.6 pounds for
2003, so Yamaha had to work long and hard to find another two pounds
to shave for '04. The engine gets new cases for less pumping loss
and more midrange, and the frame and motor-mounts are revised for
more-crisp handling. Yamaha even went to a titanium footpeg, surely
costing itself some GYT-R hop-up sales.
Part
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Change
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Goal
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Cases
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crankcase holes larger
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Reduce "pumping" loss, up
midrange
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Cylinder
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Larger cutaway holes
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Reduce "pumping" loss,
increase midrange
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Oil lines
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Aluminum construction
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Lighter by 100g
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Headpipe, guard
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Ti construction
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Lighter by 190q
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Frame
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Headpipe gussets thinner,
smaller
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Lighter by 800g
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Fork
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New 48mm Kayaba
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Better action, lighter,
improved bottoming
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Fork
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Hydraulic bottoming system
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Improve bottoming feel
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Fork
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Kashima-coat on outer tubes
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Improve fork action
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Top tripleclamp
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New anodizing, vent-hose
grommet
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Improve durability
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Bottom tripleclamp
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Clamps fork from rear
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Less tube distortion
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Steering nuts
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Aluminum
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Lighter by 31.6q
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Front-brake line guide
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New shape
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For "new school" lever
positions
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Tires
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New L/G designations
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Stiffer "YZF" carcass for all
YZs
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Engine/shock bolts
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From grade 8 to 10
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Stronger, better
torque-readings
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Front brake master-cylinder
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New diaphragm, float added
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Improve power, feel
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Footpegs
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Titanium, more ribs, cast
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Lighter by 130g, stronger
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Clutch cable
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From 8mm sheath to 6mm
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Lighter by 63.8g
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Various collars
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From steel to aluminum
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Lighter
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Seat cover
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Gripper top, sides
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Improve ride comfort
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