the h@k is a grey import similar to the sioux and the surfer and went out of production in about 1992-93, they are all very similar mechanically but subtle differences in styling, bodywork and running gear make interconnectivity of parts challenging. collectively they could be considered as precursors of the gsm and rcr. mechanically i believe the cylinders, pistons, clutches, crankcases, coolng systems are the same, the sufer and h@k have 6 speed boxes and the sioux has 4 speed. getting the right bits even used parts will take time to accumulate, you'll have to contact bob wright and trawl feebay on worldwide setting.
as an example, i am looking for a rear wheel/hub for a sioux but this item is of a different pattern to the others