I just purchased my 2002 ZX9R not long ago. The PO used Bel-Ray Super Clean as a chain lube which made the chain unbelievably dirty. The PO sure didn't look as though he took much time cleaning it [chain]. I've sense cleaned the chain and lubed it (not Bel-Ray), but at the time noticed the chain guard had a lot of Bel-Ray along with gravel on the inside. So I cleaned that out , but thought I'll bet the Primary Drive sprocket cover would need to be looked at. Well, yesterday I finally got around to pulling the cover and sure enough there it was. So, if you're not accustom to removing your sprocket cover from time to time you may want to give it a thought just to see what's going on inside there.