Originally Posted by dunlop0_1
I assume it's because they allow for temperature variants, north pole to africa if you will. I used 10/40 for ages with no ill effects apart from I was forever topping the level up. It burnt oil like an old banger 15/50 cured it.
We all thought it was pie gravey you used in your bikes, (but my god it works)
Rod Team Ghost. Ill get mi coat.