Hi,
I just did the first oil change on my 2014 SGS. I went with redline 20/50 in the engine, Trans oil with shockproof in the trans and primary oil in the primary. I've read a lot of posts and the majority of people are saying my bike only needs one quart in the primary. The manual calls for 38oz of oil in the primary and I only bought one quart because everyone is saying it only needs one quart. Well, my OCD won't let me button up my primary cover until there is 38oz in there. Seeing as I only had one quart would it be safe to add the extra six ounces using the 20/50 engine oil?
Thanks for any help or advice.

 

Ok, here is how to service the primary on any Harley Big Twin with a Diaphragm Spring type Clutch (pretty much every clutch since late `84).

With the bike upright, fill the primary until the lube level just touches the outer diameter of the clutch shell.

Now you will know exactly how much lube your primary takes, and you know how to look in there and see if it has the correct amount.

Don`t worry about under filling by a few ounces, but do not over fill.

As you can see in the illustration, the lube level when correct is quite a bit higher than the starter ring gear, so even if the level is low, the ring gear is still going to sling that lube all over inside the primary.

 

See above post good to go.
As for mixing yea you can but why . In most cases mixing won't harm a thing but why chance it a quart of F+ is just not that expensive and the primary does not need a fancy lube.