96 Kx 134

[windowcleaner]

Hello all, I am new to this forum but definatly think you guys can help me out a bit. I just purchased a 1996 kx 125 that has been bored @ 0.80, ported and polished. I have removed the top end and found this underneath.

I have been told a number of different ideas of why this could have happened and was wondering if anyone else may have any ideas? When I removed the piston from the cylinder I realized that it was a 1998 piston in a 1996 motor, could this have casued any problems? I know I have to replace the piston, rings and all, but is there anyting else that I should be concerned about from anyone else's previous experience? I was told that this could have been caused by the crank bearing "cage" is falling apart and entering the top of the piston, Is there anyway of teling which bearing is bad or even if that is the problem? Thanks for any advise that could be given

[rm250dude]

since it is bored 80 over i would be concerned about having the cylinder resleeved as for the damage on the top of the piston i would check the play in your crank bearings but it kinda looks like the piston ring may have broke

[windowcleaner]

I just found out that the piston ring had siezed to the piston, Could this have caused the ping marks in the piston head? Also, there was absoulty no damage to the cylinder walls, no deep scrapes, just a couple of scuff marks. Thanks for any advise that could be given, Jason

[ROACHIE]

well get a new piston,rings and wristpin, check ur crank left-right play=ok up-down play-no good and hone that cylinder and get rippin'!!

[FPMXer]

Did the head have the same marks?? I would say higher octane fuel, and correct the jetting. If the big end rod bearing is failing you will know by the way it looks and moves. Post up some pic's of the big end of the rod.

[windowcleaner]

Yes the head had a few of the same marks, but not as many. I have checked the crank and there is NO up and down play just minimal side to side. Even if I dont see any damage to the cylinder walls should I worry about having any work done to it?