I do hope that someone can help, I need to replace my cylinder and piston as I have been wondering since I bought this used saw a month ago that's its a bit gutless. I got my compression tester and found that its only 6 bar, about 90 psi, should be 165 psi. I would like to go 52mm big bore ie to 372xp and power, however the only decent cylinder is non xtorq, Hyway Nikasil which is faily good quality with warranty, am I making a mistake going away from xtorq which is avalable in 50mm, regards David