Motorcycle Repair: 91 CB750 Nighthawk, stator, rythm

Question
Hi Crhis,
Looking for a little expertise and a point in the right direction. I own a '91 Nighthawk CB750 with 50,000 miles. Lately, when moving (mainly at low speeds), I hear a deep knocking noise. The knock's vibrations can also be felt slightly. In my Clymer manual, one possible problem causing the sound is something called cyclinder slap. But it is only heard (and felt) when moving. Basically, when idling, everything sounds as it should. Only when I began to drive off do i hear the sound. knock knock knock in rythm, which speeds up as the bike does. So, any ideas what this could be? Anything life threatening to the bike (or myself)?

Answer
Hi Will.

When was the last total service was done?  Most bikes require a full service at 50,000 miles along with new stator.

It could be a number of things all happening together; timing, camchain tension, valves in need of adjustment, carbs out of synch could all need doing.

Cylinder slap is not a normal thing either, so just get the bike serviced and the noise should go away.

Good luck and ride safe.
FALCON