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Author Topic: What the #%$* is this noise? (solved, with road rash!!)  (Read 5372 times)

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Offline B.O.X.N.I.F.E.

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What the #%$* is this noise? (solved, with road rash!!)
« on: March 30, 2009, 05:18:12 PM »
Man, when it rains it pours. I'm coming off the highway and as I downshift from top gear I get the most horrible sound, really similar to aluminum cans dragging behind me... except it's coming from the engine, seems like left side.

The video is awful (& upside down) but you're listening for the sound between 17 and 20 seconds in. Sounds like bouncing tin cans. It does this on downshifts with the clutch engaged. Multiply this sound by about 10 and you'll get the highway speed experience.

« Last Edit: April 08, 2009, 04:03:26 PM by boxnife »
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1974 CB550

32 days and 5,536 miles on a CB550...

http://kerncountykid.blogspot.com/

and a couple years later, 38 days and 9,102 miles...

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Offline MJL

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Re: What the #%$* is this noise?? (with video)
« Reply #1 on: March 30, 2009, 05:39:36 PM »
Sounds like the trans wasn't fully engaged in the next gear.  Did you give the lever a good push or just kinda tap it?
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Offline B.O.X.N.I.F.E.

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Re: What the #%$* is this noise?? (with video)
« Reply #2 on: March 30, 2009, 05:55:45 PM »
Quote from: MJL on March 30, 2009, 05:39:36 PM
Sounds like the trans wasn't fully engaged in the next gear.  Did you give the lever a good push or just kinda tap it?

Lever was fully pulled. It does it all the time now coming down between each gear until I get to 2nd. Doesn't do it between 2nd & 1st.
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1974 CB550

32 days and 5,536 miles on a CB550...

http://kerncountykid.blogspot.com/

and a couple years later, 38 days and 9,102 miles...

Forever West

... and all of it in a 4 mintue video

<a href="Not a valid vimeo URL">WWYY?[/url]

Offline mattcb350f

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Re: What the #%$* is this noise?? (with video)
« Reply #3 on: March 30, 2009, 05:56:00 PM »
Sounds like the chain hitting the chain guard to me.

 Matt.
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Offline B.O.X.N.I.F.E.

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Re: What the #%$* is this noise?? (with video)
« Reply #4 on: March 30, 2009, 05:58:01 PM »
Quote from: mattcb350f on March 30, 2009, 05:56:00 PM
Sounds like the chain hitting the chain guard to me.

 Matt.

No chain guard!
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1974 CB550

32 days and 5,536 miles on a CB550...

http://kerncountykid.blogspot.com/

and a couple years later, 38 days and 9,102 miles...

Forever West

... and all of it in a 4 mintue video

<a href="Not a valid vimeo URL">WWYY?[/url]

Offline JS550

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Re: What the #%$* is this noise?? (with video)
« Reply #5 on: March 30, 2009, 06:07:26 PM »
Still have the center stand? Maybe the chain is slappin it?
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Offline mattcb350f

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Re: What the #%$* is this noise?? (with video)
« Reply #6 on: March 30, 2009, 06:08:05 PM »
I've heard some wierd engine noises before, but if that's from the engine it's a new one to me  :D

It sounds outside of the engine to me, and left side is the chain area. No guard rules that out but what about hitting something else, or even some bent teeth on some sprockets with make the chain make some wierd noises.

...just doesnt sound engine to me

 Matt.
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1974 CB350F,  1980 CB125S,  1981 XL80S
Non Honda's: 86 & 87 Husqvarna 400wr's

My CB350F resto: http://forums.sohc4.net/index.php?topic=30467.0
Gallery at:
http://gallery.sohc4.net/main.php?g2_itemId=298318

Offline 754

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Re: What the #%$* is this noise?? (with video)
« Reply #7 on: March 30, 2009, 06:11:50 PM »
Pop your chain cover cuz if its shedding teeth or rollers, you aint got long.. :o :o
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Offline B.O.X.N.I.F.E.

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Re: What the #%$* is this noise?? (with video)
« Reply #8 on: March 30, 2009, 06:14:43 PM »
I just rode it and it seems like you guys are right, not engine. It definetly only does it coming down through the gears and only when the clutch is engaged. The center stand is tight, but its hard to see if the chain is doing anything weird while in motion. I have adjusted it recently because it was slapping around and that didn't sound like this, which is why I think it might not be the chain.

It's so tempting to hang my head down there, but then my brain says "you're on a motorcycle dumbass, watch where you're going".
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1974 CB550

32 days and 5,536 miles on a CB550...

http://kerncountykid.blogspot.com/

and a couple years later, 38 days and 9,102 miles...

Forever West

... and all of it in a 4 mintue video

<a href="Not a valid vimeo URL">WWYY?[/url]

Offline 754

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Re: What the #%$* is this noise?? (with video)
« Reply #9 on: March 30, 2009, 06:33:42 PM »
EVEN IF you adjusted it at its tightest point, it aint gonna fix it if its WORN out.

 By the sounds of it something majorly changed or is letting go real fast.. so find it now.. or pay more later... MUCH..MUCH..MORE.. :o
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Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline 750goes

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Re: What the #%$* is this noise?? (with video)
« Reply #10 on: March 30, 2009, 06:48:04 PM »
Put it on the centrestand and run it up/down through the gears - you may be a bit better able to hear where the noise is coming from..

have someone hold the bike for you to make sure the rear wheel does not touch the ground - pretty obvious





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Offline Frankencake

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Re: What the #%$* is this noise?? (with video)
« Reply #11 on: March 30, 2009, 06:48:46 PM »
take a small screwdriver and tap around your bike with the handle.  Tap until you find the part that make the same note as in the video.  It sounds like your chain is hitting your exhaust, center stand or some other cowbell like piece of metal.  That might be the problem.  Too much cowbell!
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Offline Sporkfly

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Re: What the #%$* is this noise?? (with video)
« Reply #12 on: March 30, 2009, 06:53:29 PM »
Sounds exactly like something hitting the exhaust, so +1 on everybody else.
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Offline Bill Vaughan

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Re: What the #%$* is this noise?? (with video)
« Reply #13 on: March 30, 2009, 08:23:04 PM »
Check the wheel spokes, too.  Sounds like something is bouncing off of them toward the end.  There's four or five distinct hits.

« Last Edit: March 30, 2009, 08:26:19 PM by Bill Vaughan »
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Offline B.O.X.N.I.F.E.

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Re: What the #%$* is this noise?? (with video)
« Reply #14 on: March 30, 2009, 08:28:25 PM »
Well I checked out the chain and noticed the sprocket teeth looked more like the 'bad' picture in my manual. The chain is definetly looser than when I adjusted it last week. I'm not entirely convinced the noise is the chain, but it definetly needed replacing. So I went ahead and ordered both sprockets & a chain. Makes sense too since I have new tires waiting to go on. I'm going to hope for the best and try zip tying the centerstand tight to see if that's it.

That's it on motorcycle money for a few weeks. I was going to order up my rings & gasket set, but the girlfriend is coming home from college and expects free use of my car so I couldn't tear the bike down anyways. I did order a OEM gasket kit for the carbs, so that'll keep me busy enough for a while.

I've got a small fortune invested in the '49 Chevy, I thought the bike would be something fun & cheap to work on when I didn't have money for the Chevy. Cheap, ha!  :o
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1974 CB550

32 days and 5,536 miles on a CB550...

http://kerncountykid.blogspot.com/

and a couple years later, 38 days and 9,102 miles...

Forever West

... and all of it in a 4 mintue video

<a href="Not a valid vimeo URL">WWYY?[/url]

Offline B.O.X.N.I.F.E.

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Re: What the #%$* is this noise?? (with video)
« Reply #15 on: March 30, 2009, 08:30:27 PM »
Quote from: Bill Vaughan on March 30, 2009, 08:23:04 PM
Check the wheel spokes, too.  Sounds like something is bouncing off of them toward the end.  There's four or five distinct hits.



Check them for tension? I was doing the little 'ping' or 'klunk' test, and some of them seemed dead. I figured adjusting tension on the spokes could have some serious effects if done wrong so I didn't mess with them.
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1974 CB550

32 days and 5,536 miles on a CB550...

http://kerncountykid.blogspot.com/

and a couple years later, 38 days and 9,102 miles...

Forever West

... and all of it in a 4 mintue video

<a href="Not a valid vimeo URL">WWYY?[/url]

Offline B.O.X.N.I.F.E.

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Re: What the #%$* is this noise?? (with video)
« Reply #16 on: March 30, 2009, 08:33:09 PM »
Quote from: Bill Vaughan on March 30, 2009, 08:23:04 PM
Check the wheel spokes, too.  Sounds like something is bouncing off of them toward the end.  There's four or five distinct hits.



Oh wait, that's the sound I'm talking about. I guess it does sound like spokes, but it was def coming from the area around my left foot.
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1974 CB550

32 days and 5,536 miles on a CB550...

http://kerncountykid.blogspot.com/

and a couple years later, 38 days and 9,102 miles...

Forever West

... and all of it in a 4 mintue video

<a href="Not a valid vimeo URL">WWYY?[/url]

Offline Spanner 1

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Re: What the #%$* is this noise?? (with video)
« Reply #17 on: March 30, 2009, 08:50:50 PM »
I'm with js550, sounds like a slack chain hitting the main-stand to me too. Chain relaxes/ tightens quickly when you change gear up or down....
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Jamil20

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Re: What the #%$* is this noise?? (with video)
« Reply #18 on: March 30, 2009, 08:53:10 PM »
It sounds like you have some of these on your spokes.

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Online Really?

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Re: What the #%$* is this noise?? (with video)
« Reply #19 on: March 30, 2009, 10:09:54 PM »
Wonder if it is the chain slapping the front sprocket cover.  Like flinging up and hitting it.
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Offline B.O.X.N.I.F.E.

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Re: What the #%$* is this noise?? (with video)
« Reply #20 on: March 31, 2009, 03:36:47 PM »
Quote from: GigaWhiskey on March 30, 2009, 10:09:54 PM
Wonder if it is the chain slapping the front sprocket cover.  Like flinging up and hitting it.

All the chain talk got me thinking, and I wondered the same thing. There's no chain cover and it really seemed to be coming from the area around my left foot. New chain & sprockets are on the way, I'll post back when it's all installed.
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1974 CB550

32 days and 5,536 miles on a CB550...

http://kerncountykid.blogspot.com/

and a couple years later, 38 days and 9,102 miles...

Forever West

... and all of it in a 4 mintue video

<a href="Not a valid vimeo URL">WWYY?[/url]

Offline JS550

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Re: What the #%$* is this noise?? (with video)
« Reply #21 on: March 31, 2009, 03:54:13 PM »
Jamil20 those are sweet! Do they make em for the 750!
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Offline 750goes

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Re: What the #%$* is this noise?? (with video)
« Reply #22 on: March 31, 2009, 07:32:12 PM »
Just another thought - take off the transmission cover and see if anything falls out - like a broken spring...maybe a loose screw banging around inside ??

that would give a hollow tinking sound if something was hitting inside the case...
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Offline L.A. Nomad........

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Re: What the #%$* is this noise?? (with video)
« Reply #23 on: March 31, 2009, 07:49:17 PM »
Or the the chain guide inside your front sproket cover. I'm going with loose/wore chain slapping swing arm!


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Online Really?

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Re: What the #%$* is this noise?? (with video)
« Reply #24 on: March 31, 2009, 08:54:36 PM »
There is a rubber guide inside that front sprocket cover that could be gone and slapping on that.  Well, the aluminum that it would normally cover.
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I don't have a motorcycle, sold it ('85 Yamaha Venture Royale).  Haven't had a CB750 for over 40 years.

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