why is the yfz 450 sleeved down
Jun 9, 2003 | 01:52 AM
#4
Pro Rider
Joined: Feb 2003
Posts: 268
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why is the yfz 450 sleeved down
you can put a motorcycle yz450f rod in there and make it 450cc if you want. But they put a shorter stoke to meet the 440cc race standards. So it will rev faster but loose more top end HP than the 450cc. I dont know if the loss in compression was due to the destroking though. The piston goes up just as high, it just doesnt go down as far as the 450cc. They probably changed the compression on purpose.
Jun 9, 2003 | 01:59 AM
#5
Trailblazer
Joined: Jun 2002
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why is the yfz 450 sleeved down
The crank has less stroke, The rod will actually be longer in this motor if the compression height of the piston is the same. The loss of compression is from it being destroked. Look up pistons for a chevy 350 and 383, 383 has more compression even though it is the same piston is used.
Jun 9, 2003 | 02:22 AM
#6
Pro Rider
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why is the yfz 450 sleeved down
It is simple physics, the longer the rod is the closer the piston moves to the valves on compression strokes. This means that it smashes more air and fuel - basicly the definision of compression in an engine.
Jun 9, 2003 | 02:32 AM
#7
Extreme Pro Rider
Joined: Jul 2002
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why is the yfz 450 sleeved down
Are there any 450 stroke kits out? (Can you stroke a YZ450F today?)
Just thinking, if you were going to stroke the new quad. . . might as well stroke the $hit out of it.
Putting a 686 in my Wife's Raptor now so, wonder what these will do against it.
Just thinking, if you were going to stroke the new quad. . . might as well stroke the $hit out of it.
Putting a 686 in my Wife's Raptor now so, wonder what these will do against it.
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Jun 9, 2003 | 02:34 AM
#8
Trailblazer
Joined: Jun 2002
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why is the yfz 450 sleeved down
I am figuring that they used the same length rod. Therefore the one with the highest compression height on the piston ( the one with the longest stroke crankshaft) will have higher compression.
Jun 9, 2003 | 05:23 AM
#9
Trailblazer
Joined: Jul 2001
Posts: 51
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why is the yfz 450 sleeved down
There is a company in Europe called TUMIC who do a 480cc aftermarket cylinder for the YZF450. You would have to use the longer stroke YZF crank, which bolts straight in by the way.. You get greater coolant capacity, 98mm bore, thicker sleeve and its able to be bored out to 100mm for 498cc.
