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Offline Chris Schneiter

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Clunk
« on: April 04, 2006, 02:38:25 PM »
Last night, I started my '76CB750 up for the first time this year. A friend, who has a '96 Shadow (and is unaccustomed to weird old bike sounds) said, "What's that sound?"
It's a clunk/clatter in the lower part of the engine (maybe crank?), that you can really hear at low idle. It's been there since I bought the bike. I've never worried about it. Should I? The bike runs well, but I don't want to get stranded somewhere.
Anybody got any Idea wht it might be?
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Offline Bob Wessner

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Re: Clunk
« Reply #1 on: April 04, 2006, 02:45:29 PM »
Does the sound change, or diminish if you pull in the clutch? If so, it's par for the course, clutch rattle. It can be reduced by making sure the carbs are sync'd if that's the case.
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Offline mutters

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Re: Clunk
« Reply #2 on: April 04, 2006, 03:42:17 PM »
Does the rattle go away under load ?? if so ,it's just a ol' honda thang, bit worried about the clunk but. ???
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phylo101

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Re: Clunk
« Reply #3 on: April 05, 2006, 05:53:14 PM »
Clutch rattle, CAN be quite clunky if its bad. Nowt wrong, every heard a Ducati open clutch rattle????? wow!

Rattles because rough low speed running, allows the plates to rattle about in the clutch basket, so synching the carbs means nice smooth idling, no jerking about. Also, if you RAELLY don't like it, turning the idle speed up to about 1400rpm on the revcounter will take the edge off it by loading the engine ever so slightly, almost unnoticeably.

phylo
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Offline Jonesy

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Re: Clunk
« Reply #4 on: April 05, 2006, 06:54:28 PM »
Being a '76 you ought to have the special anti-rattle clutch basket assembly with the wave washer clutch plate. This debuted on the GL1000 and was quickly adopted to all the other bikes.
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Offline Magpie

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Re: Clunk
« Reply #5 on: April 05, 2006, 08:52:29 PM »
This article in the tech library helped mine a lot. http://sohc4.us/node/43
Cliff
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Offline Magpie

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Re: Clunk
« Reply #6 on: April 05, 2006, 08:57:09 PM »
Sorry - this one http://sohc4.us/node/44. it seems when the plates are aligned properly, like the stars, all is better. It certainly made mine quieter. That and a good carb sync so the primary chains are not being bothered by a rough idle.
Cheers,
Cliff.
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