I agree about the quick dino changes--at least that's what I've decided to do on my '94 Harley Evo engine.
The oil in a Harley Davidson engine can catch ****--to say the least. The engines run hotter than many water cooled engines, and at times they'll run cooler than water cooled engines. (Such as when you make short runs on cooler days).
If you get any condensation (water) in the oil it will need to burn off. If you can't get the oil temperature above 212F it's not going to vaporize and burn off the water. Synthetics (so we're all told) heat up more slowly, and they don't heat up as much as dinos. So it's possible that a good synthetic might be a bad idea if you're running short runs in the winter (as most cold weather rides are--
short, that is!)
You want the oil to heat up quickly enough so that it'll disperse the water...
And on fuel dilution--very common, especially on carbureated v-twin bikes. What if you dilute the oil with fuel early on in a synthetic oil run? Say you're wanting to go to 6000 miles on the Mobil 1 V-Twin, but a fouling plug or a heating/cooling issue, or a carbureator issue causes you to thin the oil with gasoline in the first 1000 miles of riding. You'll be going another 5000 miles on what may now be a light 40 weight (or worse), severely compromised by fuel dilution.
These engines tend to "dirty up" the oil pretty quickly as well--another reason for short OCI's in my opinion.
So, for my part I've concluded that a 2000 to 2500 mile drain on a good 20W50 is the way to go. I can afford more frequent oil changes with the dino, and since I do ride on colder days I think the dino might (that's
might) shed moisture more efficiently on such days.
I've gone with Havoline 20W50. I think you should do the same.
Dan