I did a search and was unable to locate info about this. So I am posting. I have an 01 WR 426 that I purchased about 6 months ago. So far so good. I have I have great compression and power and the valves have recently been checked. I have read where people ride the yzfs 1 season and then replace the piston and rings. I am not racing, nor did the previous owner. I ride it hard as it was meant to be ridden but do not abuse it. The bike has 4500 miles on it. I can hear a slight piston slapping when the engine is under load and lower rpms. It could be the 93 octane I am running since it calls for 94 in the manual. There is no gas station around my area that sells higher than 93 octane. I do add some octane booster when I am able. My question is: Do I need to replace the piston and/or rings? I just don't want to break the skirting off the piston or anything. Any advice any of you can offer will be greatly appreciated. Thanks in advance.