Spectro trans and Amsoil primary
 

I just did 3 hole change on my Ultra. The bike had records showing dealer oil changes with Syn3 in all holes when I bought it. I always use Mobil 1 in my engines, but went back with Syn3 in trans/primary when I changed fluid last time. This time, I had a gift card for a local moto shop. They had Amsoil primary, and Spectro HD 6 speed trans in stock, so I grabbed those. The bike shifts MUCH smoother, less "notchy" than with the Syn3. Don't know if its from the primary or the trans, since I changed both at same time. But I won't go back to Syn3.

It could be just the new fluids making it feel better. Usually new fluids feel better than old fluids. How many miles on the old tranny and primary fluids?

I been using Amsoil synthetic primary oil and Spectro 6 Speed trans oil for years on my SG. I am not a fan of using 20W-50 in all 3 holes. Just my :icon_twocents:.

10K on the old fluids, but it shifted hard/notchy since I've had the bike, new or old Sny3. The Spectro is 75W140. Not sure the weight of the Amsoil, it wasn't on the container.

According to the Amsoil website, the Kinematic Viscosity @ 100°C, cSt is 18.7, which specs out to a SAE 50 grade oil.

https://amsoilcontent.com/ams/lit/da...tins/g3302.pdf

Just did my 1000 mile service on the 2022 Heritage last week. Amsoil in all 3 holes. 20W-50 in motor. Amsoil primary and used their transmission lube, also. Funny how they don't list the viscosity on the primary and transmission lubes. I am also not a believer in 20W50 for the primary and transmission.

I believe that the Amsoil primary is more like a 40 weight oil. I use it in my primary and like the way the clutch works with it. Also using the Amsoil transmission lube. Both seem to work fine.

Another “my dicks bigger thread”
 

Okay then…ha ha ha

I bought a used Ultra Classic 2019 and changed the gear oil to Spectro 6 on advice of my indy mechanic and I noticed better shifting. A year later I switched to Amsoil Primary fluid and noticed better clutch release and engagement. I now use both of those products consistently.

Spectro just sold to Motorex from Switzerland