ok so i pulled the barrel off my kx 125 1991 model today as the kick starter would not move so bike would not start..

i noticed there was no coolant in the radiator

now i had a look at the piston and it seems fine( few litle chips in the top)

ring was still on piston but the split in the ring was poking out

but the barrel has a scratch about an inch long were the ring poked out

what do i need to do..

the kickstarter mooved when i put the barrel back on but then got stuck again
i am assuming the ring is hanging out and getting caught

 

something got into the combustion and marred up the piston and the cyl. head. Good chance it was that ring you are mentioning. Clean up the head and do a top end rebuild. That cylinder scratch in the photo does not look too bad. Make sure that there are no burrs with the new top end.