Don't think it should make that much difference to the bike, I work for a largeish engineering firm with over 100 vans, we quite often towed in a diesel one that got filled with petrol, maybe a gallon of diesel and 8 gallon of petrol, the bloke I work with used to run his mark 2 Astra on this stuff, quite a lot of smoke on start up, and the oil level used to fill up with all the diesel that the plugs could not burn, so might be worth changing the oil aftera couple of tank fills of petrol.