[beatr911]

RMD, Do you mean to say that Atkinson cam timing really will have no effect at light loads? Good thought. Maybe this is just folly as this engine runs nowhere near even 30% nearly all the time. I now see that Atkinson may probably be best used when an engine is in a high load situation where throttle restriction is at a minimum allowing reversion. Maybe this engine is just too powerful and a smaller, say 500cc engine would be better.

Though I do not know if the Honda NC700 series motor uses an Atkinson mode, I can see that it could be a good candidate. It has a shared intake plenum, single point fuel injection, NOT designed for high RPM and is loaded reasonably high at freeway speeds (50-ish HP). It is probably too powerful yet for maximum mpg but needed to have enough to satisfy most riders.

Mechman, yes 14:1 would be better. 10.2 static might not be enough to do anything. The losses of dynamic compression outweighing the less restrictive throttle. Lacking enough information or engine modeling tools to know if this whole exercise will yield an increase in BSFC for the power demands of how I ride the bike, I'm left to simply experiment.

Not sure what you're after with the throttle. It already has one that maintains vacuum in the intake. Would you say to increase the spring in the slide of the CV carb?