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Discussion Starter #1
Let me start by saying I've exhausted all my resources and knowledge on this one. I've searched the forums exhaustively, pored over the service manual, talked to other motorcycle owners, and I'm at a complete loss. So I'm not looking for any definitive answers here. Maybe just a couple suggestions or opinions, because I really don't even know where to start next.

I have a mystery "thump" or "clunk" sound. It occurs under braking, always right before I come to a complete stop. It SEEMS to be coming from directly below me somewhere. I've had the bike up off the ground, checked the steering tightness, the axle nut tightness, play in the bearings and in the suspension. Everything is fine in all of those areas. The noise is not consistent in how often it occurs, only WHEN it occurs. Sometimes I can ride for an hour and not hear it. Sometimes I can go 20 feet in 1st gear and hear it loudly when I stop. Only thing I haven't checked is play in the output shaft for the final drive.

I keep coming back to a brake issue, since my front caliper did lose a bolt a couple weeks ago. I replaced the bolt (used Loctite too) and checked the torque on the others, front and rear. The front pads are a little looser in the caliper than they used to be, but not enough to slide around and make that much noise. And, like I said, it doesn't seem to be coming from the front.

I also wonder if it's not something in the transmission. I did put that post up about some hitchiness in the shifting (still does it when cold). And occasionally I get a different sort of "clunk" if let the clutch out in 1st while moving already...the sort of sound like you'd get in a car with an auto that's low on tranny fluid. A sound like everything just caught up to what you were doing.

Anyway, I thought I'd at least post this because (no surprise to most 900 owners), there's not much in the way of issues with the 9 outside the weak stator. Even if no one has any idea what it might be, maybe someone else will come along someday and know that at least they're not the only one experiencing it. Thanks for your time guys, and like I said, I'll take any opinions. The noise doesn't seem to affect the ride at all, but I'd rather not find out exactly what it is under hard braking or going around a corner at 60 mph. :D
 

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does it happen when you apply just the front brakes,just the back brakes or doesn't it matter? Does it make the noise when you engine brake or ONLY when applying the brakes and just before you stop?
 

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I don't have the "clunk" under braking, but I did have the clunk taking off. Odd as it sounds, I was low on oil; my son did my change and when I asked about it, he only put three quarts in. Turns out the bike was .7 quart low. After adding the rest of the oil, the mystery clunk on take off has never returned.
 

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How many miles on the bike? Are you a hard rider? If you ride a lot and feel you are a hard rider then you may want to check the wear of the coupling dampers located in the rear wheel. Lift the bike and with it in gear rock the rear wheel back and forth while you hold the rear sprocket. Any significant play would indicate they are wearing or worn and should be replaced.
 

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Discussion Starter #5
4800 miles on the bike now. I wouldn't say I'm a hard rider, tho most of those 4800 miles have been 2-up, bike loaded down a good 50-80 lbs above Kawasaki's recommended load of 397 lbs.

combinations of brake use don't seem to make any difference. If I engine brake far enough to reach the point of deceleration where I usually hear the mystery sound, the bike's lugging pretty bad anyway. It seriously only happens in the half-second before I'm at a complete stop. About the only time I can count on it happening for sure is, ironically, when I pull into the parking log at work. I swing left, then right to line up to back into a diagonal space on the left side of the lane. When I stop to back in, I almost always hear it then. Otherwise it's a crap shoot as to whether I'll hear it at all.

Bike's not low on oil, when I was checking the steering play, I actually used a level on the triple tree to make sure the bike was truly level. Oil was right on the money.

One thing I did notice when troubleshooting the noise under engine braking, letting the bike slow down to 3-5 mph in first sure makes it want to lurch...bad. And then, as I clutch in, it feels like it almost surges a little bit. It's very bizarre. I know the clutch is adjusted properly...adjusted it then triple checked it after it wouldn't lift into second gear one day. I DO know the throttle cables need adjusted (not badly, but I should get it done), but that wouldn't have any bearing on this.

I haven't got enough experience with bikes to know how abnormal most of this stuff is, so forgive me if it seems like I'm asking questions that have obvious answers.
 

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Another check is the front drive pulley to output shaft.
No play is allowed and tightening the nut will not fix it.
 
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