I discovered that the rubber dust cover on the pushrod of the rear brake cylinder is not available for the 600 or 750ss (199s models) on its own. You have to buy a complete rear brake pump. A lot to pay for a rubber seal. Turns out that the one for the 600 monster of the same period, part number 62640131a fits perfectly and around 5£. The rubber shown here around the pushrod Might help somebody
