2000 YZ125 piston/wrist pin/bearing Q


Jul 5, 2005
I just installed a new wiseco piston, /ring, wrist pin, and wrist pin/ connecting rod end roller bearing. bike runs great and everything seems fine. this question is about something i saw on install that is really bothering me. i placed the new roller bearing set in the connecting rod end, placed the piston over rod end, slid the wrist pin through the piston, roller set/rod, and installed the clips to keep the pin in the piston. then i looked at the underside of the piston assembled, and noticed that the roller bearing set could 'walk' out of the connecting rod end about half of its width before it ran into the wrist pin supports of the piston. the piston was centered over the connecting rod, as it would be when installed in the bore, when i observed this. i slid the bearing set along the wrist pin, back into place, centered in the con rod end, and installed the bore. what i'm really worried about is the bearing walking out of the con rod end during riding, and side loading or akwardly loading the con rod, or other catastrophies that might occur. has anyone ever noticed this before when changing a piston?? i would have thought there would be something to control that bearing movement. i guess im paranoid, cuz all this went together way to well... it would be great if someone could confirm that this is normal, and once installed, the bearing set stays put, or... someone tells me to rip it down before i destroy my engine. Also, as if this isn't long enough, if anyone has ever installed boyesen pro series reeds on this engine, could you confirm that the stock reed travel limiters are not required? thanks. bin.
Oct 19, 2006
I never figured,there is about a 1/4 inch of play.I would be surprised if the actual bearing pins were engineered to not hang out,if the cage walks out at all.Should be fine.The stops will shatter the carbon stops,they will go into your engine.