Bill, when you look at Amisol's published diesel tests (top chart here)
http://www.synzilla.com/testimonials/Amsoil_vs_Shell_Rotella_T_5w-40_Syntheti...it shows that small percentages of diesel fuel getting loose in the system is a STRONG DETRIMENT to
all of the various oil's viscosity performances. Unburned fuel is a detriment in all engines, not a helper.
Gasoline contamination also hurts oil performance and it lowers viscosity too, most UOA's report gasoline contamination if found as it is a concern.
Neither gasoline nor diesel fuel are considered "helpful" to their engine oil.
Remember though,
Gasoline is much more volatile than diesel fuel. Check out the pumps at your local gas station -- spilled diesel on the pump nozzle holder doesn't even evaporate when the sun hits it.
Gasoline that does get into your engine oil does evaporate out of your sump and into your blow-by system by way of the "huff" tube to the air box. The gasoline in your oil does evaporate sooner than the water that also gets into your oil. Both do evaporate when your bike sump gets up to full operating temperature.
(over positive 212
o F boiling point for the water, only 90-100 degrees boiling point for the gasoline)
Our sump gets up to 220-250
o at road speeds.
This is why short stop and go driving that doesn't heat your engine up all the way is considered bad for your car's engine and it requires the shorter "extreme duty" oil change interval that your car manufacturer lists in your owner's manual.
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The fact that Rotella is designed to keep it's viscosity range when contaminated with fuel isn't a bad thing for our Savages.
It means is is NOT LIKE the modern MA2 bike oils that ARE allowed to drop out of viscosity range after one (1) nozzle viscosity test run when they are virgin & uncontaminated -- Rotella won't drop out of viscosity range even when it gets 2% fuel contaminated even after being tested TWICE as long as normally required on the harsher Kurt Oban test (Amisol data).
UOA tests commonly show Rotella to still be hanging in there on viscosity grade at the end of some pretty extended drain intervals on touring bikes.
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If you guys are arguing that large TBN numbers make up some sort of undefined cylinder wall problem, then you are going to LOVE the new Calcium/Magnesium additive packages that are coming out in the new SN car oils. (same stuff that used to be considered "detergent" and "buffer" for acidification)
These C/M additive packages will show up in MA2 bike oils soon enough as there is very little difference between SM/SN grade and the new JASO MA2 grade (and some bike oil bottles are now listing both sets of standards on their bottles). MA2 bike oils will quickly become a simple bottle change on the same car oil bottling line for some suppliers
(Lucas and Suzuki come to mind).
These newer SN oils don't have much ZDDP in them at all (500-700 ppm max showing up on VOAs) instead they may well start to boost organic C/M levels up to new, never before seen high levels to try to do the job ZDDP used to do.
These oils would certainly have your cylinder wall "issue" if it ever existed. SN car oils and all the new cars should have the issue right now if it exists.
Time will tell though, people do discover new stuff all the time.
What will be sad is when our newbies put these new bike oils into their Savages and munch up their upper ends and then come here asking for advice about all the persistent "ticking" and "tapping" sounds they can't valve clearance adjust away.
Heck, we have two of them on the RSD top page right now, now don't we?
Or worse, the dealership does the oil thing for them using MA2 Suzuki oil ..... and charges them big service bucks to boot for permanently screwing up their bikes.