Hi All, I am just about to order a top end rebuild kit for the NSR150SP. The only thing that stopped me from ordering it was that it seems there is no longer the A/B/C piston sizing from Honda. I am hoping someone in the know (Trev etc :grin: ) could let me know if they are aware of this. Basically the cylinder and the piston have marks on them indicating which size they are - OD of piston indicated as A B or C and inside diameter of cylinder marked as A B or C. Obviously you make sure that if you have an A cylinder and it's within tolerance, you install an A piston. Anyhoo, when ordering from PS, the dude said that now when he enters either A, B or C into the piston sizing when ordering, it automatically 'supercedes' to the C sizing. He said Honda often make changes and obviously they have done something which means that it is now only necessary to buy the C size piston no matter what marking the cylinder has on it. I said I would just triple check before placing the order as I just don't really understand how that could work. He suggested that perhaps they have made changes to the rings or something that means the small difference in diameter is no longer of consequence. What do you think of this? Just gotta get a bit more advice/do a bit more research before I order it I think.