Castrol 06116 Power1 V-Twin 20W-50 Synthetic 4T Motorcycle Oil - 1 Quart Bottle by Castrol

Harley twin cam 88 seems to like it runs quieter, I think so anyway, like Castrol oil but hate the foil seal on bottle,my advice is to use a funnel with screen! you don’t won’t any mishaps with foil in oil tank.

as expected, box of jugs of oil

I'll be damned if I'm going to pay what Indian wants for their 20w40 oil for the Thunderstroke engine. 52,000 miles with this oil and it's been great. Oil changes at 5,000 miles as recommended for the OEM oil, and I never have to add oil in between. Blow by into the airbox is the same as the OEM oil. Cold starting is the same in the winter (mornings as low as 25F). I also ride in 120F-plus desert weather, which is hell-on-a-hotplate, but the bike handles it better than I do. I've even used an IR thermometer on the cylinder heads and seen no difference between OEM oil and this, with hundreds of readings taken at different times and ambient temperatures. Clutch and shifting action are unchanged between Castrol and OEM. I've also used Valvoline's V-twin oil though and noticed no difference, so this is certainly not a religion for me. It's mainly that Castrol as a good V-twin oil and a good high-zinc oild for my air-cooled VW Baja Bug, so I stick with them out of habit.

I am very happy with this oil I "feel" shifting is smoother and summer rides are well sheer protected. However the deciding factor for purchase was this Used Oil Analysis (UOA) which showed this oil after 5000 miles high in both moly and zinc since both values go down with mileage for them to be this high after 5000 miles means the virginal oil was quite high in these values - which is a good thing (and why I buy this oil). Other oils can be half these values or less.

Harley Davison motor transfer case and transmission