Depends on what you mean by "car gearbox oil". Most if not all bikes come with a 10W30 motor (engine) oil in them from the factory. You will even see that listed in the owners manual.
As long as its not one of the "energy saving" oils with additives it won't hurt the clutch.
If you mean ATF (automatic Transmission Fluid); yes a lot of people run it as well.
Like the others have mentioned, I use Bel-Ray Gear saver 75W or 80W. By the way, gear oil uses a different standard, so the 75W is similar to ATF and the 80W is similar to a 10W30 for comparison. And make sure you don't get Bel-Ray 80W Hypoid gear oil, its really thick and meant for differentials.
80 85 transmission oil buy at any bike shop
Oil capacity for the gearbox on 2002 Yamaha YZ85 is 500cc, after overhaul 550cc according to my book.
It should just use the engine oil for the transmission but I could be mistaken. I've never even heard of separate transmission fluid on any motorcycle or dirtbike.
half a quart!
SAE 10-30 Oil .8L or .85 US Qt.
The correct ratio for 1991 85hp Yamaha is 1:50. 1 liter of oil for 50 liters of fuel.
Trans. oil capacity - 0.5 litres
gl4/75-85
Transmission: 15W50
Yamaha
All the Origin motors have a Petrol/gas:oil ration of 50:1 That is 1litre of oil to 50 litres of Petrol
so of them will