Jaz240 summarizes it pretty well.

These miniature two cycle engines have little hardware inside BUT all must be in acceptable condition. Do check for crank pin/conrod bushing wear,and bearing condition. I'll take care of the light liner scratches & pitted piston

Last Saturday at a local track in my area I chatted with one of the guys in the pits, whom in last year sent me a WS7 P&S set with 4 + gallons fuel on it, fallowing race his air filter fell off. In short, a light hone and polish removed the liner scratches in addition to an average resizing of the cylinder to adjust for the excessive piston wear and set was ready to be reinstalled with a my suggested reasonable re-breakin. I usually suggest heat cycling 4 times or so on the bench and on the ground for at least 6 tanks, at temp & running on the rich side. If I remember correctly from last years conversation with him at one of our local tracks (well over 12 months ago) he did half of the above described suggested re-breakin. To make a long story short, I was advised last Saturday that engine has ran another 5 gallons since service, without even a conrod change. He changed the conrod one time approximately one gallon before my reconditioning-resizing service, around the 3 gallon mark. The crank shaft to bearing wear is at this time excessive he told me, and a "A" main racer on a budget he is, "gona run her til she busts", so he says. Good luck to Brian M, his racing endeavors, and even more his family life.

The method of my madness