Originally Posted By: wileyE
I posted the link to show that there is some truth in the slippery debate, it's not totaly myth despite what oil marketeers web sites say. Is it a problem fro clutches, not likely.
The marketeers are also to blame for the slippery synthetic rumors IMO. Yes even amsway. Early on they are the ones that made all the low friction and better mpg claims and even advised against break in. Some these claims still exist today with some brand followers. Claims of more power and better mpg, yet denying any difference in friction coefficient. One of the claims isn't true, or is just purely exaggerated.
Apple-oranges. Sure, but a harley is more like the diesel than many higher revving gas engines. The cam and cam bearings turn at 1/2 engine speed which is quite slow. A stationary diesel may run at 1800rpms with cam speeds of 900. Under what it takes for the parts to get up on a oil plane. A harley is capable of more rpms, but in reality most are used just loping around at diesel like rpms. Why for both it's important to have as much protection from the basestock and antiwear add as possible. Being synthetic doesn't equate into better protection in this regime.
Harleys and diesel engines share almost nothing in common. All reciprocating internal combustion engines have cams running half speed of the crank, but Harleys (except V-Rods) are air-cooled, have dry-sumps, and run on gasoline. Since they have low compression engines, their parts are not subject to the same stresses as a high-compression diesel. Also, they don't deal with the large amounts of combustion blow-by products that can taint oil with acids and other chemicals. Hence HDEOs have different add packs to deal with these problems. Since large Harley clutches don't share engine oil, there is no reason not to use synthetic oil especially considering how hot these engines get in "parade" mode. However, many of you consider the Harley shops to be the "ultimate" authority on all things motorcycle, so we are wasting our time trying to influence your oil decisions. Just keep using the straight 60 weight conventional oil that many shops were recommending just a few years ago and don't worry about a thing. "Them 'er tough engines!!" Just for grins, find out what type of oil is used in the Harley factory flat-track racing bikes and that will tell you alot about what Harley considers proper oil for their street engines. You Harley riders do know what an XR750 is, don't you? And I know you all know who Scott Parker is, right? The Michigan Mafia too?
