Some believe that it is bad luck to ride a motorcycle owned by someone who has died. They don't have to have died while riding the motorcycle for this to be true. The idea is that if the deceased catches you riding their old bike, they'll swoop down out of the blue and knock your butt right off it.
I once owned this old Suzuki GS1100L. It was a full dresser in its past life. Then it suffered an unfortunate meeting with a moose, which of course it lost. The couple I bought it from had bought the wreck and fixed it up as a naked bike, the fairings and baggage having suffered most of the damage. I have no idea how damaged the rider was in that crash, or whether they made it out alive. I do know that regardless, I never crashed that bike myself.