OK, I have ridden for 33 years, old Triumph's then BMW's. Even a Guzzi and a Duc in there. I worked in a BMW dealership for 10 years, but this is my first Harley. My buddy sold it to me and I have done a lot of work on it over the years. I have always used Mobil 1 in my engine, trans and rear end. BMW 10w in the forks. I just wanted to know what you like in the primary, trans and forks. Is Syn3 the way to go in everything? (not the forks) Thanks

 

I think the previous owner of my bike used Syn3 in all three wholes but not sure about the forks! I'm in the process of changing to Amsoil 20w-50 in crank, primary, and gonna run severe gear 75w-110 in the trans.

 

Ya, the trans and primary are what I'm really looking at. I know BMW transmissions love synthetic 75w-140. They shift a lot better. The forks?? 5w, 10w 7.5w??

 

It doesn't really matter what oil you put in. I doubt you can find any evidence of damage due to oil issues.

I use Mobil 1 in the engine and could probably change it in 10k miles but I do it as the factory 5k. I use Royal Purple in the primary and Redline Shockproof in the trans. This way, I can tell what is leaking by the oil color!

 

I switched to mobil1 V-twin 20-50 in motor and pri,, Mobil1 75-90 gl in the tranny last yr. completely happy with these

I tried Bel-Ray 80-140 in the tranny, just to heavy for our Ind weather. shifted to hard untill the motor was really warmed up. But its wasn't a syn GL so that might have been part of the problem.