My scooter "Honda PCX" mannual says: gear oil, 10W-30, MB, SL which is also the recommended engine oil.
I found motorbike gear oil specs: Motul, 80W-90 GL-5 and Speedmaster, 85W-140, GL-5.
Huge difference by the look of numbers, 10W-30 v.s 80W-90 even 85W-140, and API SL v.s API GL-5.
So...