usually its because of some type of problem (road bike) but i'm sure racers do it as part of maintenance.
If you have low compression or burning oil then you can usually assume that the rings are worn or the valves, valve seats, guides or seals are worn. While you have the whole top end apart you might as well replace all gaskets and seals because it's inexpensive. You can measure cylinder and piston inner and outer diameters and decide if you want to replace them but im sure most people will go ahead and replace them or just bore over with a new piston. valves get measured stem to guide clearance as well as out of round for both. anything worn gets replaced. if one is bad might as well replace all of them. seats can either get cut or replaced, but i'm not sure if many people replace the whole seat anymore.
2013 Speed Triple SE
Riding Game Challenges: 15
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