Quote:
Originally Posted by Grant-53
The main point Craig stresses is that less air drag means less power is needed which means less fuel burned. The compression ratio is a key to thermodynamic engine efficiency. Mass rate of flow of air/fuel mixture is a function of displacement and rpm. The light high rpm engines are favored for racing and may have a slight advantage with less overall weight. A long stroke, lower rpm engine may burn less fuel and have a broader torque band for street riding. A well designed shell will reduce drag, provide ample cargo capacity, and offer more crash protection. The bulkheads on my tail box are 9mm aluminum honeycomb to protect the back.
|
That's way over my head but thanks for it. I've got a theory in my more primitive mind that my bike has less potential for improvement with respect to optimizing mpg via weight reduction, higher gearing, and being more slippery at highway speeds than an equally-well-engineered engine with displacement that's just a little more than one-third the size of mine, like the Kawasaki twin 250 or the Honda single. However, I'd guess that there is still lots of room for improvement through gearing optimization and drag reduction even though it may not be to the same level.
I Would love to see Honda's 670 cc twin and Honda's 471 cc twin and the single 250 or 300 with the full streamlining effect just to see the potential of all of these engines when given the maximum effect like are the Vetter-designed bikes; mainly because they are so amazingly efficient already in stock form. Comparing the 670 to the other two would be very interesting to me since it's sort of a total different engine strategy for motorcycle propulsion; more like Fred's diesel strategy, but with spark ignition instead of compression ignition; or we may say it's more of an automobile approach; instead of a traditional motorcycle approach. It's not so important really to show that larger displaced engines can reach the same level as the amazing Honda 250 or 300 single (which we also don't know), because I don't think it can; but I think that there are others besides me who prefer the broader torque band and prefer that engine character, and so it would be interesting to see what the penalty would be for driving a lower-revving, more torquey bike.