BMW K100 K75 radiator side covers. BMW K100 K75 radiator cap. These radiator caps are a nice addition to the BMW K75 and K100. They can be used for a Cafe racer, Scrambler, Tracker and so on. You get more air on your radiator so it will improve the cooling of the engine. Besides that, there is no need to adjust the tank because the sides are covered by these beautiful polyester parts, do keep in mind these have a rough finish and could be necessary to sand/prime before paint.