Thanks Steve!!

But, remember our discussions on vacuum, volume and velocity?

That's where I get humbled and I'm still trying to learn.

There's a established knowledge base among Harley tuners, who consider volumetric efficiency (volume inducted divided by displacement)and flame front velocity (helps decrease combustion time).

These factors can permit retarding advance to gain more power, something practiced more outside of the Harley scene due to antiquated design. This seems like a paradox at first glance against old timing lore ("advance till she pings and back off&quot. But, if those factors can be improved, running less advance produces more power, because it reduces "negative" force of sparking the mixture as the piston travels towards TDC (retarding timing).

That's why I've wondered about potentially significant differences between the R* motor and Harleys. We have 4 valve heads and I suspect some well thought out intake design and combustion chamber design, aimed at those factors (and possible more improvements in post 04 design). Add to that, our ported intakes, which lead to our discussions on the three "Vs".

SO what do we have? And how do we understand how best to tune it? Most of us "hit and miss" on what feels better or dyno the bike, which limits us to WOT measurement.

We're at a disadvantage, since R*s don't have time and following of really knowledgeable tuners (at least I haven't found or read anything that addresses R* engine intake design like what's available for Harleys). Here's a good link to an example of Harley tuning support:

http://www.daytona-sensors.com/tech_tuning.html

p.s. has suggested AFR values at different RPM, which you can convert to CO

But, even if we did understand, we don't seem to have an ignition system we can tune to exploit our R* advantages.

Or do we?

Consider this. The Dyna can be set to aggressively ramp up. I suspect the R* (un-corked) can handle it (more than a Harley). But the at high RPM, I think there's too much advance. If only we could run the most agressive curve and "clip" the max advance a few degrees...

I recall the Dyna has a retard override (put there for NOS or whatever). How about 2 VOES switches (or one with some trick connections) that work both curve switching and high advance (low vacuum) override??

That would be a fun experiment in theory and might pan out in practice. If only we had the time...

Jim