Dull regular thud/clonk

1976 kz900. Annoying problem.

I have a dull thud/clonk, with almost no actual noise, as I ride. The frequency is directly related to road speed, occurs in all gears, clutch in or clutch out. As best I can calculate, at different constant speeds, the frequency is somewhere beteen 260-320 "beats" per mile. This wold suggest one beat per 17-20 feet. This would seem to rule out a tire or chain problem as I would expect a tire problem to occur every 7 feet or so and a chain problem to be approx every 6 feet.

Seems to be less pronounced as I accelerate but maybe more pronounced as I brake.

Could this possibly be a front wheel bearing problem? What is the correct torque for the large front axel nuts?

Thanks.

BH

wheel bearings, yes, chain, yes, could be a chain alingment issue, or even a bad sprocket front or rear, just going to have to look at each item until you find it

BSKZ650 Thanks your response.

I actually removed the chain at the weekend, very thorougly cleaned and re lubed, working each link back and forth, to it's full limit of travel, thinking this was the problem. It obviously wasn't (maybe?). i'm thinking any other chain or wheel related problem would manifest itself at either the wheel circumference or chain length?

My confusion is that the thump occurs at 17-20' of road travel and this doesn't SEEM to relate to either the chain length or the wheel circumference. That's why I arrived at the wheel bearings?

My thinking is a bad roller hitting a bad spot/crack in the outer race? I'm thinking that any given roller might pass the same point on the outer race every two revolutions of the wheel?

BH

Thanks so far but no other thoughts or suggestions?

Check all moving parts as others have suggested. I think its your heart beating really fast because your riding a KZ.

Have you tried putting her on the centre stand and weighing the back down so the front wheel is in the air and then spinning it? If you touch a bit of wood onto the bottom of the forks you may hear a noisy bearing[with the other end in your ear!]Just a thought.

Could it be a bad spot on the chain lining up with a bad tooth on a sprocket? That would lower the rate of occurrence.

With chain removed from bike, could "ride" bike while being towed or coasting downhill to determine whether symptoms still existed.

Good Luck!

I went thru wheel bearing problems, but mine was due to after market wheels, and the spacers not being correct, gotta love POs.
since you have eliminated the chain and sprockets, my next thinking would be cush drive, wheel bearings, and poss, bad tire

I was noticing a clunk on my bike, but only during hard braking. I later isolated it to the triple tree being a bit loose.
Could your clunk be related to a loose tree, or some suspension problem. Maybe regular bumps in the road and suspension issues?