This is a queston we are always asked by our customers. Hands down we recommend our V-Twin approvesd #707 20W-50 racing oil. This product has the extra zinc these Harley's need for the main rod bearings. The oil is great for the seals to prevent leaks becasue of its conditioning package added to the oil. Most Schaeffer customers can see aproximately a 9000 mile change interval no problem.
Here is a list of Harley engines:
ENGINE: Twin Cam, Evo, Ironhead, Sportster, V-Rod
Recommendation: #707 Schaeffer Supreme V-Twin Synthetic Plus 20W-50
ENGINE: Flathead, Knucklehead, Panhead, Shovelhead
All prices are in USD.