I have had a Z-1 Classic I bought new. It is misses and literally bogs...mostly in cold weather. It is intermittant. When it happens it will usually recover when I (a) close the throttle and reapply it or (b) shift up or down. It has happened in all gears and anywhere between idle and ~ 3000 rpms. It ´purrs´ like a kitten at 60 to 80 mph on the highway. Anybody experience this???