syclone, I don't think its about the top-end. It's all about the bottom-end. I don't think there are single-crankpin/flywheel water-cooled engines (asking not stating). These engines use crankshafts instead. The single-crankpin 45deg design, is what makes the sound, and allows the stroke required to make the torque that you can't get out of high revving engines, as Harry states below. That's why I'm concerned about this type of engine being around much longer. This design is not very efficient and eventually, they're gonna hit the wall with EPA and kaboom, it's over. [highlight]However, I think Harry knows something he's not telling us![/highlight] [smiley=confused5.gif]
Hoist!
Its not efficient in present EPA form...not because of the common crankpin..but because the compression has to be kept down (8.9-9.2:1) because of the combustion chamber temps ,and the resulting NO and NOX emissions that result...HC's may have to be controlled with a catalyst, but lean mixtures and high temps send the NOX through the roof.
A combustion chamber and piston dont care what they're pushing down on.
Now drop the head temps 100 degrees... 1) you can raise the compression ..and the corresponding cam specs....and the specific output goes to 1.25 hp/cubic inch lets say..and the Hp cant go up without a torque rise...so you have a 96" motor now making 120 hp , or a 110 making close to 140. 2) The timing curves now allowed along with the lower chamber temps means NO and NOX emissions can be controlled....and it will still go "potato=potato"
Hell..two valve ZO6 Corvettes ,,running at over 11.0:1 compression..are on the street right now. A water cooled aluminum head is the only way it can be done..an iron head wouldnt cut it.
the Mother Company's biggest challenge through all this will always be....the SOUND. It's what makes a Harley a Harley,,,it's the soul of the bike...it whats lusted after by so many...it's what enables you to know it's a Harley from a block away....."IT" is what sells the bike to 95% of the customers( who will never visit a site like this)....... its the common crankpin. I wish them the best of luck.