NEED help kx125 crank and rod problems

Hi im new here so work with me if you can...I have an 99 kx125 and i took a compression check and it was about 65psi. I new that wasnt gonna cut it so i pulled the top end off and the ring looked like it may have been overheated and collapsed. Also i was looking at the rod and the bearing on the crank is shot..The rod and the crank have a little blue shade to them.. Is this bike bad about crank problems or do you think a owner in the past may have run it low on oil... What kind of job is it to dig out the crank? I guess you have to split the case.. Ive done lots of car work over the years but never split a bike motor before...Thanks in advance for any help you can give MATT AYERS [email protected]