Can I run synthetic oil in the primary case. Thanks Max

 

i run royal purple synthetic oil in all the holes never had a problem. some of the bikes have quieted down too

 

IMHO I wouldn't. Synthetics are to slippery for friction clutches. I believe that many of the slipping clutch problems are caused from synthetic/ fuel efficient additives in the primary. I'll stick with HD for now but I am seriously considering ATF.

 

I,ve been using Royal Purple Synthetic Manual Transmission Fluid,I wouldn't use ATF,too slippery.

 

I have been using redline MTL synthetic which is like a thick ATF. Dealer put in formula + and I don't like the feel of it because it slips & grabs. Going back to syn.

 

Both Redline MTL and MT90 have no moly in them. Neither does HD Syn3. So none of those have the fuel efficient additives you are talking about.

 

If you read the lables on oils like Mobil1 or Amsoil, and I guess most of them, the oils for "Motorcycles" are made to be compatable with wet clutches. Not just Harleys.
Thats why I would not use oils for autos in my bike.They have those additives in them. Though Harley says in an emergenct diesel oil can be used. Must have less of those additives.