I took my bike 2018 HD Fat Boy S in for its 8000km service and they wanted to change the oil in all three holes. They say they do that every service, in the manual that's every other service first third fifth etc. I told them not to, as I had Amsoil in there and I didn't want it replaced. Do you guys change primary and tranny oil every service?

PRimary yes , but not trans

my view on this is. Oil is cheaper than parts, so I do it often, and Yes I run Amsoil all 3 done at the same time, again oil is cheaper

I use Motul in the Engine (Change it every 5000km)