So I've got my '81 CM400T running very well. Starts right up, idles steady at 1200-1250 rpm, and accelerates well. Seems like it's happy place is around 5000 rpm; plenty of power and torque there. I spend a lot of time in the 4500 to 6500 range; never approaching 10K redline. I have, however, noticed somewhat of a flat spot below 4K. Sitting in the garage running the throttle through the full range it's fine, but if I let it fall below 4k running down the road thats when I notice a flat or rough spot. Just wondering if that's normal for this bike. FYI - bike is stock down to original tires and tool kit.