Motorcycle Repair: 1980 CB 650 Custom, cb650, finger nail

Question
I just recently purchased a 1980 CB650 custom and the guy i bought it from removed the head because it was burning a little oil, from the looks of it only two cylinders are leaking oil through the other two look fine.  My question is can i just change out the rings or would you suggest just putting in all new pistons maybe one size up and boreing it out, speedo says it has 8900 miles on bike, and the previous owner said its been sittin for about 7 years, then he rode it last year and at first it ran great then it started burning a little oil.  Which is the reason he removed the head.

Answer
Adam, anytime you remove a piston you should deglaze the cylinder and replace the rings....all of them.  You can tell if the cylinders need bored by the depth of the ring ridge at the top of the cylinder.  If you can catch your finger nail in the ridge, it's time to bore it.

Regards
Rich