I need to find the where I can fill gear oil of my Honda beat scooter?

I need to find the where I can fill gear oil of my Honda beat scooter?

If you are talking about the final drive oil, you can use a regular API SG 10W-40 or the same oil you put in the engine. There's a drain and a fill port by the final drive housing around the rear axle (rear tire).

There's a screw-in plug on the top of the motor/trans housing, on the right hand side of the scoot

You can't. You're obviously not smart enough to do that.

If only you could download a pdf of the owner manual from the internet.

LIke dude, 90-weight gear oil is 90-weight gear oil. Walmart carries.

Check the owners manual?