Safe to mix Mobil1 with Redline Tranny fluid?

[OldNerdGuy]

I would not mix them, they are two completely different types of oil. Different additives, different viscosity, different functions. The Reline oils are special purpose. The Primary oil contains friction modifiers for the clutch. These are not found in motor oil. The Transmission Oil is gear oil, which is different from Motor Oil. Besides, the Redline Transmission Oil is Pink, the Mobil1 is Orange. The colors would clash

I will say this. My bike runs much quieter, and better, since I switched to Redline in the Primary and Transmission, using their specific oils for each function. I still use Mobil1 in the crankcase.

[tdkkart]

1qt is usually enough to fill the primary just to the bottom of the clutch spring, which is all you want, and all I've been doing for almost 15 years.
The other day I had my primary cover off, so that ALL the oil was out, then it needed just a few extra ounces.

I reality it's a chain, sprockets and a couple bearings, all of which is just happy as a pig in mud to have any lubrication at all , let alone a full quart of "primary oil". I've run just about everything you can imagine in there, ATF, motor oil, gear lube, 10w-40, 20w-50, synthetic, Dino, etc with no real noticeable difference in any of them. My go-to oil is usually some brand of 80-90w gear oil, seems to work fine other than it stinks a bit, and it REALLY stinks if you burn up a stator.