Jan, I'm sorry, but it's not the castor oil that causes the bearings to go bad, on the contrary, it's what helps them to avoid rusting and wear. It's the methanol that causes the rust because it's hyposopic and will draw water right out of the air and place it right on the bearings, causing rust. Castor will thicken up over time and cause the bearing to be hard to turn, but can be cleaned right up with some fresh fuel.