The oil fill is on the right side of the bike (as i f you were sitting on the bike), just to the rear of the right rear cylinder. You may have a chrome cover so you may need to remove it.
That is where you add the oil.
Honda 10w40 works well
I use Motul 10w40. Check with your local dealer.
On the right side there is a chcek glass it is hard to see
3 1/2 quarts. There is a sight glass on the lower right side that shows the oil fullness.
If you look at the diff. you will see a drain plug and a re-fill plug. Check with your local dealer for the right oil.
No
The filler cap on the 1200's is on the right side, ( foot brake side ) right near the dip stick.
you remove the GoldWing cover on the left side of the bike above the passenger foot pedal
Yes, it is. However, there is separate gear oil in the final drive of the Goldwing, as it is shaft driven.
same as the engine oil
My owners manual for my 1984 Honda GoldWing says to use SAE 10W-40 Oil.