GP Customs
Tech
Predicting Power
BHP=PLAN/33000
P=Effective pressure
L=Piston stroke in feet
A=Area of piston in square inches
N=Power strokes per minute
I)Crank Train: So what exactly are we talking
                       about when I say Crank train?   

       *Well its a combination of piston,piston speed
                  as well as ring width,crank case volume,
                  bearing surfaces etc...

      
Note: Think of it as a train with the tractor
                  being the crank itself diving the rods
                  pistons rings all depending upon each
                  component for optimum performance.
                  Each item effects the performance as a
                  whole. Everything in motion is part of the
                  train. Everything....

      A)Pistons and rings:
              *Most pistons manufactured by the japanese
                manufactures have a higher silicone content
                than some aftermarket manufacturers. And
                silicone content is the name of the game
                when avoiding melting holes at higher
                Temps. For that reason I use off the shelf
                pistons unless ring width and flutter
                becomes an issue....
              *Ring width and flutter affect piston speed
                and sealing along the cylinder bore.

Example: Standard rings will begin to flutter around
              60,000ft/sec
2  in most two stroke street bikes
              or 7000RPM. So why use them? well they
               provide longevity and sealing far superior
               to the narrow racing ring which remains
               stable towards 10,000RPM. There are even
               kit rings that remain stable even higher in
               the RPM range. But what you do lose is the
               low RPM seal and durability.
              
So why use them?,...They perform along with
              the crank @ Crank train allowing for higher
              sustained power in the upper revs. But you                
               ride a modern
GP machine so its been                           
              designed far beyond the days of
RD350s.

                                          * CIRCLIPS*
              Never install circlips in the 9 or 3 oclock
               positions! Remember how fast the piston
              and ring are traveling? They will spring out
              and catch an exhaust port,...or the wrist
              pin will move out into a transfer port!
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