Ah... now i get it. I was thinking of some minor grease stains, oil leaks, n stuff, pain in the neck to clean them off my own car's engine block, but yea I didn't think of the fact that they get time between the races to clean them. How neglectful. okay, that's great to know. Thanks a lot, fellas.
I also did notice the the stainless steel exhaust pipes don't bronze as much on these bikes, which i guess now should be explained as that they don't really get that much mileage. I had my "luck" of trying to repolished a half year old bronzed 4-1 header for my car through wetsanding, and man, that thing was practically brown the entire way.