Chainsaw Repair

Willard, what would be the advantage of just using that single ring?

371/2 prolly the best saws ever built?

Advantage of the single ring is less friction making higher rpm. The disadvantage is durabilty and a slight gain of crankcase volume but the added rpm / hp makes up for the difference, especially if only used for a short chainsaw race.
Yes the 371/372 has come along ways from the 266/268/272. That little extra stroke length of the 372 seems to be the final design improvement along with the air injection that makes these saws so strong.
BTW I know a fellow down the street who has a brand new 1992 272XP that has never cut a stick of wood. Once a year he idles it for a few minutes to keep it limbered up. I'm tempted to buy it from him.

Willard.