I was told by the seller that he used Mobile 1 20w-50 in all 3 holes... oil, trans, and primary... ok or No?

 

believe that only the vtwin mobil one has the friction modifier for the primary. standard mobil 1 in tranny and motor is ok though.

 

I bought mobile 1 v twin synthetic 20w50. I dont wanna waste or ruin bike. Im def a rookie

 

Did he give you the owners manual, or a service manual? I doubt if those oils are the recommended ones. In over 40 years of Harley ownership I have always used suitable oils that meet the recommended specs. I currently use Mobil 1 20/50 in my S&S engine, H-D primary oil and Redline in the trans.

 

No luck on manuals

 

Yep! If it's the Vtwin variety it will say right on the bottle it is okay to use. Lot of people run it in all 3 holes. I'm currently running it in the engine and primary and using the M1 75w-90 syn gear oil in the tranny.

 

If your bike is recent you may be able to download a free owners manual from the H-D website. Go to the Owners tab. Otherwise get yourself a factory service manual, which will answer many questions and help service your bike.

Frankly there are so many different types of 'advice' available for our Harleys, many of which are best ignored, that I strongly recommend you use the H-D book as your starting point. Otherwise you may find you never make your mind up!

 

Owners manuals
https://www.harley-davidson.com/cont...rs-manual.html

Also see if you can ask the guy if the what he used was the Mobil 1 VTWIN 20W50. Which others have said they run in all three holes. Probably better than running SYN3.