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How does the 450 engine compare to the MX bike ? Has it been detuned for lower range torque,or does it have the same horses,compared to the MX bike ? The YFZ450 engine is mildly tuned,compared to the MX bike.

Any dyno reports ? Crank or chassis ? Rwhp in stock form ?
 

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No clue myself but at the press release Kawi claimed 43hp rear wheels. Not sure how much you can say to be believing in that, but that's what they told us all. I know a local place here is dynoing a stock one this weekend I think though.
 

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Couldn't tell you for sure, but it wouldn't suprise me; yamaha did the same thing- the comp on the YFZ is 11.4:1 and the YZF is 12.3:1. Don't ask me why they do it though; maybe like you say; for low end torque?
 

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Saw a dyno chart today of a stock KFX at a local dealer. 43.3hp stock at the rear wheels was what they got. An LTR did 43.1hp there also.
 

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QUOTE (Blue Bull @ Mar 28 2007, 08:47 PM) index.php?act=findpost&pid=775
How does the 450 engine compare to the MX bike ? Has it been detuned for lower range torque,or does it have the same horses,compared to the MX bike ? The YFZ450 engine is mildly tuned,compared to the MX bike.

Any dyno reports ? Crank or chassis ? Rwhp in stock form ?


no, it is the same motor, but kawasaki changed the bore and the stroke on the quad. and put in a 5 speed tranny, only difference
 

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QUOTE (Renegade Racing @ May 14 2007, 12:10 PM) index.php?act=findpost&pid=1867
no, it is the same motor, but kawasaki changed the bore and the stroke on the quad. and put in a 5 speed tranny, only difference

No??????????????????????!!!!!!!!!!!!!!!!!!!
here they are
KXF450F_________________DIRTBIKE________________________________________________
__
valve timing
Inlet: open 32 BTDC
close 72 ABDC
duration 284

Exhaust: open 62 BBDC
close 42 ATDC
duration 284
Ignition timing BTDC 10dg @1800
comp 12:1
______________________________________________________________________________
KFX450R 4 wheeler
valve timing
inlet: open 26 BTDC
close 70 ABDC
duration 276
Exhaust: open 82 BBDC
close 24 ATDC
duration 284
Ignition timing from 10dg [email protected] to [email protected]
comp 12:1
________________no posting the lift!_________________________
yes the motors are a little diff..
the kx brings in more fuel and holds it longer in the cycle, or lets go of the charge latter in the cycle.
kFX smaller fuel charge, and letting go of the fuel charge sooner in the cycle, say 20dg sooner(Exhaust side)
check out the crower intake cam for the KXF450.
Bore and stroke ARE the same.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
you all can run down to the dealer and pull both (2) shop manuals out, turn to valve timing and specs, and check it out for your self...................
Yes the tranning is a 5 speed kfx, 4 speed kxf
 
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