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TOPIC: Clunking Sound

Clunking Sound 10 years 1 week ago #156191

  • Norseman
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Hi, Folks.

Hoping some one can point me in the right direction. Recently I have noticed a "clunking" sound and feel when starting up from for example a red light. It only occurs in lower gears (1st & 2nd) and only under load (acceleration). It seems to come from left side just inside the shifter. The bike clutches and shifts fine, accelerates fine, but clunks and jerks a little. It is quite audible and I definitely can feel it.

The bike has only 12K miles on her, engine runs great, valve clearance exactly at nominal, carbs synched with Morgan Carbtune, fresh oil (Valvoline 20W50 for motorcycles), everything works great. It doesn't pop out of gear, there's plenty of power, no slippage, I haven't done a compression check, but everything checks out.

But before I park the bike (my only bike) and start tearing it down and splitting the case, etc., I thought I'd ask you folks what you think and what you would do in this situation. If there are things I can do or check before I shut down my riding season, I would really appreciate it!!!

Post edited by: Norseman, at: 2007/07/11 16:08

Post edited by: Norseman, at: 2007/07/11 16:10

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Clunking Sound 10 years 1 week ago #156203

  • The Milkman
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For some reason a few guys here have had the nut come loose in the front sprocket. I'd check that and chain slack. But, then I don't know if you have chain or shaft drive.
Ride safe

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78 650-C2, Stock engine, Jardine 4-2 Exh., 17-38 sprockets, dyna ignition and coils, coil wiring mod, carb mod.

Clunking Sound 10 years 1 week ago #156205

  • Norseman
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I will definitely check the front sprocket nut, and yes, I do have the chain drive. I checked the chain slack by pushing the bottom center - chain travel is roughly 1.5 inches from gently pushed-down to lifting up. I don't know exactly how to correctly check slack.

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Clunking Sound 10 years 1 week ago #156256

  • tjettim
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Check your front and back sprocket bolts.I set my chain
slack at 3/4 to 1" movement max while I am sitting on
the bike.On the center stand,motor off,put the trans in low and rock the wheel back and forth listening for
noises.Also check the rear hub for movement.Sometimes
the rubber dampers deteriorate over time.

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Clunking Sound 10 years 1 week ago #156296

  • Kiwiz
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I agree With the foregoing check the chain first.


I had this on my newly rebuilt J and feared the worst; particularily as I had been having some clutch lifter issues. However all it was was maladjusted drive chain.

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Clunking Sound 10 years 1 week ago #156525

  • Norseman
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Thanks, Guys. I did check the chain, which had a generous 1.5" travel. I adjusted to 30mm (roughly 1&3/16". That helped significantly, but I still feel a slight "clunking" feeling through the footpegs. I really don't think it's my imagination, so I will tighten the chain just a tad more to 1".

What's bothering me a little is the "clunking" does not go away when I pull in the clutch and just coast in any gear. I did check the front sprocket and everything was nice and tight (I did take off the locking collar and checked the bolt). Teeth look fine on rear and front with what I assume is normal wear for 12K miles.

If anyone else has any suggestions beyond what I already have done, I'd appreciate it. Thanks!

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Clunking Sound 10 years 1 week ago #156530

  • RetroRiceRocketRider
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When you adjusted the chain, did you use the little "lines" on the adjuster brackets to line it up?
They aren't always exact, even when set on the same "line" on both sides.

I always use a tape measure to measure the distance the ends of the bolts are from the brackets once I get the chain at the proper tension, and have never had any probs with proper wheel alignment.

If they arent set the same when measured, then what you might be hearing is the master link as it rolls over the smaller teeth on the front sprocket.
It will obviously be more pronounced sounding at lower speeds, since higher speeds (and a 4-into-1 exhaust if so equipped) will usually drown out anything below a dull roar.

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Covina, So Calif!
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Clunking Sound 10 years 1 week ago #156535

  • Patton
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Perhaps overlooked, but see nothing about having actually lubed the chain. Am guessing original chain, which probably requires regular lubing as routine maintenance. Without lube, the chain will kink. Would lube the heck out of it and do another test run. :)

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Clunking Sound 10 years 1 week ago #156537

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Perhaps overlooked, but see nothing about having actually lubed the chain. Am guessing original chain, which probably requires regular lubing as routine maintenance. Without lube, the chain will kink. Would lube the heck out of it and do another test run. :)

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Clunking Sound 10 years 1 week ago #156696

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Thanks for taking time to respond, Retro and Patton. I did use the "lines" on the swingarm when adjusting, and it did seem to me to be a rather inaccurate reference. I will definitely use a calibrated measure to check and re-adjust if necessary - so thanks.

Patton, I did lube the chain with a product called Maxima Chain Wax (recommended by dealership that mounted my new Dunlop tires). However, after just a few miles (less than 50 miles) the wax was flung off and the chain and sprockets look bone dry again. I'm not sure what the best chain lube is, so if you have any suggestions, I'm all ears.

Now, the clunking doesn't seem to correspond with chain speed/links, but it definitely got better after tightening the chain. So my plan of action is to fine-adjust using an accurate measurement as recommended, and then lube the heck out of it, then take a test ride. Will report back. Thanks again, all who responded!

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Clunking Sound 10 years 1 week ago #156699

  • BARNEYHYPHEN
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Is it a CLUNK or could it be somewhat "softer"? could it be a badly balanced or just a bad tire?

FWIW, I "align" my back wheel by checking the measuremnet (spelling?) between the sidewall of the tire and the inside edge of the swingarm, at the front of the rear tire and making sure both sides are the same.

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Clunking Sound 10 years 1 week ago #156729

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Well, I measured the distance between the very rear of the swingarm and the inside of the adjustment bracket, and I was .5mm off. I lifted the bike off the rear tire and adjusted to exact distance and tightened everything back down and took it for a test ride. What do you know - clunking disappeared. However, my alignment slackened the chain a bit, so now I get to tighten it again:lol:

This time, though, I will tape down my own lines on swingarm and bracket on each side before loosening wheel and adjust 1mm on each side, maintaining alignment.

My conclusion is that even 0.5mm difference at rear of swingarm translates to enough misalignment at front of rear sprocket to cause noise/feel issue. If that's the case, the crude lines on the bike are useless in really truing the rear wheel. Also, the factory minimum spec on chain slack of 30mm seems to generous as I'm currently at exactly 30mm now and I have noticeable "slop" when shifting (sorry about my highly technical terms of clunking and slop, but it seems to accurately describe my perceptions LOL). It seems that tjettim's method of 1", or 25.5mm, may be more effective, although that might be because the chain is somewhat worn?

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Clunking Sound 10 years 1 week ago #156730

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I have a clunking noise just as you describe. It is more pronounced if I don't give enough throttle as I pull away from a stop. If I give a little more throttle the noise doesn't appear.
I asked this same question maybe 6 months ago and someone here said to check the starter clutch. The person said that the bolts holding the starter clutch come loose from the factory torque settings but cannot back completely out because they are inside the stator cover. I haven't gotten around to tearing down my bike so I can't say for sure if this is what makes the clunking noise on my bike.
Grant.

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1981 KZ1000 CSR
1983 KZ750 Project Bike
1990 550 Zephyr
1994 KZ1000 P

Clunking Sound 10 years 1 week ago #156735

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Well, that sounds reasonable, and could account for my condition. I looked at the drawing schematic on Kawasazki.com, and also my KZ1000 factory manual. What I have difficulty determining is in order to check the bolts, do I need to remove alternator rotor to get to the bolts to check, or can they be checked by simply removing the cover?

It's a shame actually - I just had the cover off to replace the gasket due to a small oil leak at the rubber wire plug just two weeks ago. Now I will have to drain the oil, remove the cover, check, then clean the gasket sealant around the rubber wire seal, re-apply and hopefully the gasket will seal again. Someone wrote a song about "wish I knew then what I know now". LOL

Oh well, them are the breaks... I'm a perfectionist (not that I ever acheive perfection - just an annoying behavior trait, really), and really want to get to the root cause and correct. Any input or insight on checking this potential cause is greatly appreciated!!!

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Clunking Sound 10 years 1 week ago #156742

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I will check my manual to see what it says about getting to the starter motor clutch and let you know what I find out.
Grant.

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1981 KZ1000 CSR
1983 KZ750 Project Bike
1990 550 Zephyr
1994 KZ1000 P

Clunking Sound 10 years 1 week ago #156755

  • twinkyrider
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I don't drain the oil to take off the alternater cover, I lean the bike against a wall and chuck the wheels. My neighbor replaced his leaky alt. cover gasket but didn't silicone the rubber grommet where the alt. wires come out and still had a leak. Let us know if your starter clutch bolts were loose, I may have the same issue.

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78 kz1000A
Fond du Lac,WI

Clunking Sound 10 years 1 week ago #156787

  • Norseman
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Update - got the alternator cover off and checked the starting clutch gear (large gear), the starting clutch assembly, and all seem nice and tight. Granted, I did not remove the alternator rotor, which would need to come off to physically check torque on the starting clutch assembly as the bolts run home from the engine side into the rotor. Removing rotor appears to require a special "hold" tool to remove primary nut.

Nevertheless, if the starter clutch bolts had become loose, I would imagine there would be some play between rotor and the starting clutch assembly/gear - which there is not, everything is on tight.

At this point, having ruled out the above issue, and I assume the clutch itself would not be the culprit based on the nature of the clunk sound/feel, that leaves the following items:

1. Chain slack/wear
2. Wheel misalignment (corrected)
3. Transmission (shifts fine, at 12K should be insignificant wear, no contaminants in oil, noise/feel remains with no-load)

I will re-assemble, tighten chain slack/travel to 1 inch, verify wheel trueness, test ride, and report back. Thanks again to everyone who has responded and contributed. I hope this exercise is useful to some of you guys!

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Clunking Sound 10 years 1 week ago #156804

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In closing out this thread, I test-drove the bike. No audible noise detected, slight "clunky" feel remains, but I'm not sure that it is part of the drivetrain as it no longer feels centralized like it did. After aligning the rear wheel and tightening chain slack to 1 inch, I believe I took care of the issue.

The slight feel that remains may even be my perception and excessive expectation; after all, the bike is 27 years old, chain-drive, and assembly tolerances in 1981 were not held as closely as they may be today as evidenced by the need to drop my engine somewhat just to slide the clutch cover off.

Conclusion? Slightly misaligned rear wheel coupled with excessive chain slack. Back full circle to what the initial post responders suspected and advised. Kudos to you guys! Thanks again to all of you who helped me work through this issue, you're a terrific group on a great forum!!!

Walter

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