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Thread: WR 450 Gear Ratios

  1. #1
    Does anyone know the individual gear ratios inside the transmission for the Yamaha WR 450, both the quad versions and the bike versions? Also primary and secondary gear reductions if any and what their ratios they are?

    jason

  2. #2
    Does anyone know the individual gear ratios inside the transmission for the Yamaha WR 450, both the quad versions and the bike versions? Also primary and secondary gear reductions if any and what their ratios they are?

    jason
    Jason
    CalPoly SLO

  3. #3
    Senior Member
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    Melbourne Australia
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    Will advise when we get back to Melbourne next week.

    Cheers
    Geoff Pearson

    RMIT FSAE 02-04
    Monash FSAE 05
    RMIT FSAE 06-07

    Design it. Build it. Break it.

  4. #4
    Senior Member
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    This seems to have the info required:

    http://yz450f.yme.com/pages/default.htm

    Ben
    Tyre Analysis Engineer - Caterham F1 Team
    Alumnus of University of Birmingham
    www.ubracing.co.uk and Formula Student Design Judge

  5. #5
    Here's the spec's from that site.

    Type
    Liquid cooled, 4-stroke, single cylinder, DOHC 5 valves
    Displacement 449 cm3
    Bore and Stroke 95.0 x 63.4 mm
    Compression ratio 12.5:1
    Max. Power N.A.
    Max. Torque N.A.
    Lubrication Dry sump
    Fuel supply Carburettor (FCR39H)
    Clutch type Wet, multiple disc
    Ignition C.D.I.
    Starting system Kick
    Transmission Constant mesh, 4 speed
    Final transmission Chain
    Gear ratio 1 1.929
    Gear ratio 2 1.563
    Gear ratio 3 1.278
    Gear ratio 4 1.05
    Primary reduction ratio 2.818
    Secundary reduction ratio 3.357

    Um...there's one really important thing that this engine seems to be lacking. Anybody?

    Maybe the quad version has it?
    UNM FSAE 2003 to 2005

  6. #6
    <BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Um...there's one really important thing that this engine seems to be lacking. Anybody?
    <HR></BLOCKQUOTE>

    If you're talking about an electric starter, the wr450f engine has it, but the yz450f does not. The wr450f also has a 5th gear.

  7. #7
    Senior Member
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    Location
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    The WR electric start bolts onto the YZ engine, from what I can see, but you need the WR rotor cover casing and a few gears and stuff - could be quite expensive.

    The WR450 is a five speed, and I think the YFZ450 ATV is as well, but from the parts listings I have they are different gear ratios. I'll check all this when I get home, probably Monday next week.

    Cheers all
    Geoff Pearson

    RMIT FSAE 02-04
    Monash FSAE 05
    RMIT FSAE 06-07

    Design it. Build it. Break it.

  8. #8
    Anyone got a dyno chart for it? I looked around on the net a bit and couldn't find one.
    -Mike Waggoner

    The older I get, the faster/harder working I was...

  9. #9
    Here's a "half throttle" run off this website:
    http://www.cyclecost.com/shopping/po...r_now_dyno.htm



    You could scale it up to whatever you expect the peak power to be. YMMV

    Also, it's a CRF 450, I don't have a clue how that compares to the WR450.
    Alumni, University of Washington
    Structural / Mechanical Engineer, Blue Origin

  10. #10
    Wasn't somebody getting ~70 hp out one of these engines...seems like a great hp/weight ratio!
    How much do these weigh? I think the F4i weighs in at 120lbs, can't remember if this was wet or dry. Anybody got a torque curve to share?
    Also, Is the WR450 a dirt bike?
    UNM FSAE 2003 to 2005

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