RE: Need a little p.a.w. advice
Whoopee,
I've noticed, on occasional PAWs with long-bolt uppers, that the head bolts NEED to be torqued in carefully. Uneven tightening can tilt the cylinder slightly, enough to show a bind at some point in a revolution. My blue-head .09 has 3 long bolts through the cooling cuff and into the lower case. With this and other PAWs, I've had good results by tightening down the uppers with the backplate off, watching for the conrod big end 'walking' fore and aft. That is, obvious sliding fore and aft in the +/-90° from bottom dead center.
A tilted sleeve doesn't mean much if it is across the case - the shaft, rod and piston pin bearings can handle that. Tilt fore or aft does not align with rotation allowed by the bearings.
Final check is with the sleeve and cuff attached, and compression well reduced. The only resistance through a full rotation should be the natural compression, not anything like a mechanical bind. IF such a bind is felt, slack off each head bolt a half turn and recheck. If free then, tighten each bolt an eighth of a turn and recheck. If not, back off another quarter turn. If the bind reappears, go back to the last free, loosened, position, and try a different sequence, an eighth of a turn at a time.
You'll soon find a sequence that stays free of mechanical bind down to where all the bolts are fully seated. ...Takes longer to describe than to do.
The advantage of the screw-on .049 and .061 method is that alignment is guaranteed. The disadvantage is that it is more complicated to make sure the uppers are tight enough. A problem common with most, if not all, such systems. PAWs don't have spanner flats or holes for a pin-spanner... as with Cox glow heads, or several screw-top diesels.
My .09 is a delight, and very economical on fuel.