I don't think so. The flats on the pinion were not melted at all & I was doing verrrrrry long full throttle runs up and down a beach so the cluch was not constantly being used. In fact the cluch probable just engaged the once as I pulled off so it would have produced no heat on it's own, and I spend the next 5 mins blasting round in huge ovals and figure eights
So I still think it was a combination of full power, dry gears, and sand causing the gears to terminally get together in the ultimate mesh!
Ian F.