Well, I hope this doesn't look too silly! It works, but as you can see, starting is biting chunks out of the aluminium I glued in to reduce the cup's internal diameter. Anyway, the original Villiers cup must have been about 53mm across internally (minimum 50mm) and 45mm high measured from the top of the flywheel (maximum 50mm). So the Chonda cup might do, but it will still need spacing upwards.
