HI Gents,
I have an S model, could not get an air filter to suit the S model for love nor money, the M model is too short and small in dia, the A model is to big to fit the S model filter frame.
Because the U.S. did not get the S model to the best of my knowledge, aftermarket filters are not made if the S model.
I ended up cutting out the gauze frame out of the S model air box, leaving the centre post to later use a A model removable gauze filter frame & filter cap.
This allowed me to use an A model air filter which is easier to purchase & service because the filter gauze frame comes out with the element.
I have an M model Uni filter here & an OME M model air filter as well.
Regards Gibbsy