you can hone them and throw in a new set of rings, if there isn't any deep scoring going on. also, keep an eye on the bore diameter tolerances. if the bore gets too big or out of tolerance by like .001"-.003", the ring end gap will be greater and there will be more compression lost through the larger ring end gap. not to mention too much piston to cylinder clearance. can you say "broken piston skirt"? if you just run a common kd tools engine hone through it for 20 sec, you won't be opening up the bore much. try to get the crosshatch marks at like 45-60 deg angles. my uncle who worked for bombardier for 17 years, told me they tested blue marble oil and it was horrible. he would not recommend it to be used in anything. if i were you, i would run some amsoil dominator, as i have had great luck running it in all my toys.