Recently rebuilt my friends 2000 cr125 top end, (new cylinder,piston,rings,ect).After starting up he complained no power nd low compression.Stripped it back down nd discovered that the cylinder the shop sent me was a "A" nd the piston "B".Everything looks ok,nd the shop when they checked with honda said this combo is ok.Anybody have any similar problems?Also the ring end gap is .020",is this ok?