There are a few. Amsoil used to recommend Amsoil 10w-40(AMF) Motorcycle oil, but now that HD has the new screaming eagle tri-syn 20w-50 that can be used in all three cases, Amsoil states you can also use their 20w-50(AMV) motorcycle oil. Please note that the Amsoil motorcycle oils are the same as the car oil, just a different label.
The retail price for the Amsoil 10w-40 is $5.85 and the 20w-50 is $6.55. If you purchase it from an Amsoil dealer on this site, you may be able to get it cheaper. Even if you can't, the 10w-40 isn't much more than HD's primary fluid & the 20w-50 is much cheaper than HD's tri-syn 20w-50.
There is also Golden Spectro, Mobil 1 motorcycle oils, and I'm sure there are a few I forgot. There are plenty of synthetic motorcycle oils. There are also a few synthetic diesel oils than can be used for this situation. In fact, the "bob" in "Bob-is-the-oil-guy" runs a Schaeffer's synthetic blend in his bike with no clutch problems. As a rule, most try to stick with a 10w-40 (for the primart only) that doesn't use molybdenum as a friction modifier due to possible wet clutch issues. Most car oils have moly & some diesel oil also have moly. Therefore, it is a good idea to stick with motorcycle oils.
I will be putting Amsoil in my 93 FXSTC very soon (with the exception of the tranny which will get schaeffer's - a personal preference). I will change out all fluids before it goes into winter storage and run them from spring to next year at the same time - I'm planning on about 6-8k miles next summer.
I almost forgot 1 thing -
[ October 26, 2003, 11:06 PM: Message edited by: medic ]