I'm a new harley owner, neede oil late at night and used SuperTech 20W50 Motor Oil in my flstni. Is it safe to say I need to go have an oil change?

 

As long as you used the same viscosity as what was in there to begin with your good to go.

 

I had same issue except, I have 2001 FSXT. I was the the shore and needed to top off but the only oil available was 10W30. I added 1/2 qt. Was also told to get oil change. Whats the verdict?

 

From a 36-year mechanic: Run it 5k miles then change & you're good to go. Oil can be as simple or as crazy as you want to make it...
As for topping off with 1/2 qt 10W-30, same advice.

 

The Supertech is actually rated pretty good on the oil forums. Run it a while.

 

well im not sure what was already in there. Is it ok to mix oil like that? Also the supertech 20w50 did not say it was synthetic, does that matter?

 

You can mix dino & syn, as well as different viscosities, all day long and it's fine. You can verify this at any oil company website.

 

If it doesn't meet the oil spec listed in your manual, change it.