Did my YZ250F with diesel, ran it for a about 20 seconds (On a stand) running through the gears and operating the clutch. Drained and repeated. That was 3 years ago and admitedly I haven't raced much in the last 2 years but no noises, other than the usual, no clutch slip or any side effects I can tell of.
Diesel contains oil and was often used in hydraulics in the old days.
Viper666