Vintage BMW Motorcycle Owners

Hey Gang,
I'll be acquiring a conversion bike in a few days. The engine in it is a 1974 R75/5.
I plan on using the Valvoline VR1 40 for the engine.
I want to double check with you all and confirm that it's okay to use the Sta-Lube Gear Oil SAE 85w90 for the transmission/drive shaft and rear drive?
It's API/Gl-4 oil.

I've got a Clymer's manual coming in the mail too.. but wanting to buy my oil ahead of time.

Thanks!

Rob

Forgot to ask..
What are the capacities for the trans/ drive shaft/ rear drive?
I'm guessing to the bottom of the threads for trans and rear drive, but was kinda hoping for an amount so I can purchase the correct amount.

Thanks!

Hey Skyler-
You can access an owner's manual in the knowledge base.
That'll give you oil recommendations and capacities.

Myself, I do use the Valvoline VR 1 engine oils, and the Sta-Lube in the drivetrain;
the Valvoline having a good amount of ZDDP and the GL-4 being hypothetically safe for yellow metals.
Both available off the Amazon.

Synthetics may be a slighty better oil but, (to me) not at the frequency of change with these bikes.
Best-
George

Whenever I've done the driveline fluids on my /7, it always takes more than 1liter, so buy 2. As for the capacity in the driveshaft, I would measure 150cc and call it good. I've never been able to understand how you measure the fluid level through the hole with the driveshaft in the way. Generally, anything between 100-150cc will be fine.

My only issue with GL-4 is a couple of things. First, I don't think there are yellow metals in the /5-on bikes. There was some talk that they are in the pre 1970 bikes, but honestly, I don't see the side of the road littered with broken down /2 bikes. Second, with the improvements in the helical gear sets, I think you're better served with a hypoid GL-5. It is designed for the newer style gears and meshing.

Thanks guys!
I'm getting a bit excited about this upcoming purchase.. appreciate the input from you all.

Rob