Hey Tim, unsure what you mean about a two piece head. She unbolts as a one piece, but is this what you mean. Will try to grab a number off it tomorrow as I don't have power inthe shed. Good buy when you consider it has new shafts, clutch, piston, rings, crank eyc . Is in standard trim but to lift the head and do the ports and put in a hot cam would make it sweet. Built it to be a good learner bike for speedway but son has gone in a different direction. Less worry about injury in elite swimming but I can guarantee its more expensive. Just to give some an idea with the Olympics son has been in the oz silver development squad for 4 years . Gold is the Olympians. His support 4 t-shorts and 4 towels. Gotta say I was predicting this years result. Not much interest inthe kids. Lookin back rather than looking forward.