will the royal purple effect the clutches if I run it in the primary

 

Use the Max-Cycle and you should be fine.

 

Harley says SYN3 in all 3 holes is fine so Royal should be just fine.
I for one don't subscribe to the Syn 20-50 in the three holes.
In the primary I use Spectro primary oil, I believe the Syn is to slippery for the clutch. Engine I use 20-50 Syn (Amsoil) and the transmission get 75-90 Syn (Amsoil).
Just me!

 

Look on the back of the bottle for JASO MA which is the rating for wet clutches. The Mobil1 4T 10w40 is an excellent primary oil. So is Castrol Power 4T 10w40. You can find them at Autozone or AAP.

 

90 weight gear oil is the same weight as 50 weight engine oil.