Looking at your Italjet it looks like it should have a green frame, engine, rear mudguard and tank. The gearbox holds a heap of oil, I think it was 1.2 litres. I have also read that with the bike flat the oil should reach the bottom of the clutch adjusting screw plug. That is the gold bolt thing in the middle of the primary case. I can`t remember what weight oil is supposed to be in them I think it was a light gear oil around 10/30 weight or so. I think. I`ll check for you tomorrow as I don`t have the information here at home. Yours is an early model. Graham.