couls worn crank bearings on an 86xr80 cause high rpm mis-fire? my xr80 breaks up at high rpms and so far i have checked the valves they r speck. the carb is stock. new plug cam chain as tight as it can get. how tight should it be? also i can grip the flywheel n pull it in and out about an 1/8 on an inch. it also has some up and down movement and a little side to side movement. could the points gap being off cause high rpm misfire? when its reving it will shoot puffs of smoke out as it breaks up. any thought? also i have a service manual. how hard is doing a case split and crank bearings?
