OK, thank you guys, i don't feel the shifting is getting worse, I just kind of feel, that the bike put a lot km in seems like bad condtions behind in short period of time, and i will make him a treat by changing oil and filter. I feel kind of sad to push him so hard, but then again, this bike of mine never showed any sign of less powered motion cause of overheating. I felt we both enjoyed every km we have made.
Oh, well, i'm still a noob and my senses should get precise, not to neglect my PimpSerS... Thanks again guys!