August 1, 2012 7:38 AM PDT
Hello guys/gals, hope you dont mind hearing my 2 cents worth (about the worth of it at times). If all of will notice, around 2002 and up, Harley went to an all synthetic oil for all of their engines (by the way, all air cooled engines are, in fact, cooled by the oil as well). I am a certified Harley Technician, as well as an amsoil dealer. I do know that the old VW engine (air cooled) is NEVER to be run with ANY synthetic oil, because the synthetics, as good as they are with lubrication under high stress, are not so good at pulling the heat off of the engines internals. This is why everybody has taken notice of the Big Harley tendency to run so hot. If you will go back to the standard 20w50 Harley oil, or even the straight 60 wt oil, you will notice the BIG difference in engine heat being shed off on you. Instead it will be going into the oil, as your oil temp will increase greatly. This will cause you to change oil more often. But be sure to NEVER , EVER run an oil designed for an automobile in your motorcycles, no matter what brand name bike you ride. The automotive oils have friction modifiers in them, where the Motorcycle oils are blended for high heat with good lubricity, and to work well with the wet clutches found in 90% of motorcycles today. It is better, in the air cooled engine, to run a petroleum based oil instead of synthetic for this very reason. Sure, I know Harley went to the synthetic and recommends you, the customer to do the same. There are some reasons for this, but none are enough to offset the heat related issues with the air cooled engines. If any of you were ever into VW air cooled engines, it never mattered how big one built the engine, the standard oil was all that would keep it cool enough to run consistently. Some of you may have heard of Gene Berg, the man who done more for the life of Hot Rodded VW engines than all others ever. He is the one I learned this lesson from, and he was always right on. Now that he is gone, his sons, who still run his company, still have this information listed on the web site ;
www.genebergenterprizes.com. I hope this helps some of you to understand the nuances of the air cooled engine and its special needs, as we all know how much hotter they run in comparison to a water cooled internal combustion engine and the great importance the oil plays in cooling.