I have a 1994 Yamaha Seca II. It’s used oil ever since it was new (about 4oz. every few hundred miles). I always use Yamalube 4-cycle 20W-40 oil. I used to have a car that burned a lot of oil, so I have about six quarts of 10W-40 laying around.
Is it okay to use “car” oil in my bike? Or do I have to use “motorcycle” oil?