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Old 09-27-2012, 08:26 AM   #14
ST4s
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Joined: Jul 2007
Oddometer: 39
The latest theory in multicylinder race engine design is to NARROW the firing angle to allow the drive tire to regrip the race track (much disputed by Kevin Cameron with a lot of math to support his supposition). Yamaha's Cross Plane Crankshaft actually has all the firing pulses occurring in a 90 degree, I think that is the angle, period with the remainder of the crank rotations not powering the tire until the next firing sequence. Kawasaki newest ZX10R has a similar concept with the crank designed to fire one cylinder then shortly later two together then one again (Yamaha's design is patented). All of this to narrow the power production period from an inline 4's traditional 90 degree firing angle. I believe the AMA actually banned Harley Davidson from running big bang motors in dirt track racing because it gave them an unfair advantage over traditional firing V-twins.

Cheers
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