Yet another "clean up junk which shouldn't been on this bike in the first place" -- Nichols engine breather will stop the oily mess that collects on the rear of the engine. Its reed-valve is made from thermo-plastic which will breath more easily and last longer than any knockoffs made of carbon fiber, etc. This is also the only product of its kind which comes with a spanner wrench and takes only minutes to install. I'm very happy with this assembly since it significantly improves the breathing and return of the oil back to the engine's crankcase.