PIONEER +1mm STROKER VERSION, with optional ceramic bearings NOW COMES WITH A HARD CHROME OWNER REPLACEABLE SLEEVE. An Optional welded crankshaft to help prevent crank twisting is a $45 upgrade.
You can get either the 26 or the 29 Pioneer with a +1mm stroker crank now, that makes them 27 cc or 29.5 cc. Either engine will rev about 1000 RPM higher with the stroker and because of this they come with slotted big end connecting rods for better lubrication and cooling of the big end of the rod. The stroker option adds $120 to each engine.
See below for dyno graph and photo of slotted rod crank.