I did phone Norvil & they assured me that the kit should fit no problem, but some crankcases did not have the boss round the short bolt properly finished, leaving too much sticking out. If I attack this with a file they reckon it should go in no trouble. The boss on mine does have a lot of spare metal & this was getting in the way, so this will probably be the solution. Just out of interest, the old outer rubbers were deformed so the tube was nowhere near the centre, this must be due to the weight of the engine on them, so I reckon that with the Mk3 spring device fitted it would stop uneven wear on these rubbers & extend the life. Perhaps I could lash a few bungees under the tank!