TOPIC:

Im working on the said bike and tried a test ride the other day. On the lift everythings as it should be but when i pull in the clutch and start letting it out to take off i get a wierd buzzing sound. It does this through all gears. You can hear it change as you sqyeeze the clutch to change gears. Put it in neutral and let out the clutch and the buzz goes away.I dont think the hub bearings bad because i would think that would make noise even in neutral. So is it the clutch plates or maybe it needs new springs?? Clutch doesnt seem to be slipping.

Did you do a basic clutch adjustment? .... note: on some models the clutch release adjusting screw should be turned counterclockwise first until hard to turn then clockwise 1/4 turn. This is the way it's done on my 1981 KZ650-CSR.  some manuals are ambiguous about the direction, while others are wrong.

Yes basic adjustment was done using the mid cable adjuster, the adjustment screw on the sprocket cover, and theres about 1/4 inch slop between the lever and the clutch perch.

I should note that not having a service manual, i adjusted the sprocket cover screw untill it touched off then backed out about 1.4 turn and tightened the jam nut. What just came to me is that maybe i shoud have tightened the jam nut with the screw touching the drive rod. I was just thinking the buzz is from the drive rod vibrating. Sound plausable?

Adjusted the sprocket cover bolt in untill it touched the drive rod and nothing changed. Turned it out so it was sloppy and nothing changes.Guess i have no choice but open it up and look at bearngs. Odd that it only does it when in gear and the clutch starts to engage to move the bike. I ordered new steels and frictions so those will be all new. 

Bad transmission shaft bearings?

Ed, wouldnt you think that if it was a transmission bearing it would stay the same loudness regardless of clutch pulled in or not?  Thing is that while rolling and you squeeze the lever to change gears it almost goes away. Shift and release the lever and its back at the same pitch. Ive never heard this sound before and ive been into many KZs ad Ninjas.  Im gonna put it on the lift this weekend and put it in gear then slowly release the clutch to put everyhing under load to try and pinpoint the origin.

If one of the output shaft bearings is bad, the bike will make noise when the rear wheel is turning.  Clutch in or out won't matter.  Sorry, I don't know what to suggest other than perform more testing to see if you can focus in on what conditions are required to make the noise.

chuck hahn wrote:

Ed, wouldnt you think that if it was a transmission bearing it would stay the same loudness regardless of clutch pulled in or not?  Thing is that while rolling and you squeeze the lever to change gears it almost goes away. Shift and release the lever and its back at the same pitch. Ive never heard this sound before and ive been into many KZs ad Ninjas.  Im gonna put it on the lift this weekend and put it in gear then slowly release the clutch to put everyhing under load to try and pinpoint the origin.

It would make sense that when you disengage the clutch and remove engine load from the transmission that a bearing noise could change (same as a car wheel bearing that makes a different level of noise when cornering and changing the load on the bearing) also when the wheel is driving the trans in place of the crankshaft the load is reversed on the trans components

So today i opened the clutch cover and started the bike for maybe 30 seconds (just long enough to  see and hear what was gong on). Vibration came from rear of outer basket. Remember i rebuilt the hub to replace the rubber pucks per the rebuild tutorial. What i rebuilt was a spare basket i had taken apart off a 650. Same basket as the 550 setting side by sde on the bench. So what i thought was bad hub bearing. Took clutch apart and i could move the outer basket a little while on the bearing.
So i got the gear from the original 550 basket and it was pretty tight on the bearing. So i took the 650 basket apart to retrieve the new pucks to put into the original 550 basket. I also though just maybe those 3 dampener springs in there might not be pressing good against the baxking plate so i gave them a little stretch
So where im at now is new rubber pucks moved into the original 550 basket with the slightly stretched springs. i got new 6MM screws on the way home and will reassemble the original 550 basket and see what happens. THEORETICALLY tighter fit on the bearing and a lot more spring pressure against the backing plate should quiet things down considerably.

Got the new cover gasket and friction plates and reassembled everything today. Noise is gone. Dont know if it was the 650 basket, the dampener springs or what but its done and noise free