Deaton: sorry, I don't have many answers,as I bought the saw from sawking on ebay & all I know about it is it has the thin ring piston & 175#s compression w/ no release valve. It almost pulled my arm out the 1st time I started it, because of a half vast effort. It came w/ a 32" bar, full chisel,3/8x.063 full skip chain. Burying it lengthwise in an 18" walnut log didn't slow it down.I ripped that 6' log in ~4 minutes.I have 36" & 42" bars for it, but have to change the sprocket tips to .404 to use the milling chain I bought. I have to change out the drive sprocket also. I bought an Alaskan Mill that I hope to use at the GTG. Hope to get it all done Fri when I'm off work.Maybe after Sat. we'll both know alot more about our 2100s.