Knocking sound when shutting off throttle in gear
#1
09-08-2011, 02:59 PM
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Knocking sound when shutting off throttle in gear
Hi and thanks in anticipation of some assistance. Two days ago I became the proud owner of a 1994 CBR1000f. Rode it 84 miles home, non stop and felt totally relaxed afterwards - great start I thought!
I've been out on it tonight and I am experiencing a hard knock around the engine sprocket area each time I back off the throttle. It doesn't happen under load, only when backing off the throttle in gear.
The engine sounds sweet when its running whilst stationary and something tells me that it isn't the infamous Cam Chain rattle. I would assume that this would rattle even when the bike is out of gear and stationary?
Can anyone help with a possible diagnosis please?
I've been out on it tonight and I am experiencing a hard knock around the engine sprocket area each time I back off the throttle. It doesn't happen under load, only when backing off the throttle in gear.
The engine sounds sweet when its running whilst stationary and something tells me that it isn't the infamous Cam Chain rattle. I would assume that this would rattle even when the bike is out of gear and stationary?
Can anyone help with a possible diagnosis please?
#3
09-09-2011, 01:27 AM
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Knock when shutting throttle in gear
Thanks for you help adrenalnjunky I'll check it out this weekend and let you know what I find. Its brilliant that I can get help like this.
#4
09-09-2011, 02:03 AM
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Hey Stuart , mate , I had to pull your thread down here ( our Hurricane home base) so the guys can help out ...
I would put money on a drive train issue ...
Maybe not a missing tooth? , but hey , when the chains and sprockets get old on these bikes , they will ****** and grab as they go round , especially if you tensioned it and it has a tight spot in the chain some where ...
A real easy test is to whack her up on the center stand and spin the wheel by hand , watching the chain to see how tight or slack it gets in different positions mate ...
Check for excessive slack in any one spot ? or a tight spot where no slack seems to be at all ...
as well as what adrenalnjunky said of course !! damaged sprockets will cause all manner of noise when the load is off them under deceleration especially ...
cam chain ???? lets not go there as yet till you check the drive train out thoroughly....
....
I would put money on a drive train issue ...
Maybe not a missing tooth? , but hey , when the chains and sprockets get old on these bikes , they will ****** and grab as they go round , especially if you tensioned it and it has a tight spot in the chain some where ...
A real easy test is to whack her up on the center stand and spin the wheel by hand , watching the chain to see how tight or slack it gets in different positions mate ...
Check for excessive slack in any one spot ? or a tight spot where no slack seems to be at all ...
as well as what adrenalnjunky said of course !! damaged sprockets will cause all manner of noise when the load is off them under deceleration especially ...
cam chain ???? lets not go there as yet till you check the drive train out thoroughly....
....
Last edited by CBRclassic; 09-09-2011 at 02:07 AM.
#5
09-09-2011, 10:39 AM
It's a pretty active forum here mate, you're in a good place
Fill in the details on your profile so we know your rough location, or at least what country you live in, we have members from all over the world! That way if you need help or parts we can help you out better.
BTW welcome to the forum
#6
09-09-2011, 11:23 AM
I had a tight link in a chain a few years ago. I have no idea how it got tight, maybe sitting during the winter. It was just one link. When backing off I would hear a clunk, under power...nothing. I usually heard it when costing into towns with throttle backed off.
I replaced the chain and all was well.
If you want, loosen the chain a lot and push the rear wheel forward. Rotate the wheel checking each link for free movement. That's how I found mine.
I replaced the chain and all was well.
If you want, loosen the chain a lot and push the rear wheel forward. Rotate the wheel checking each link for free movement. That's how I found mine.
#7
09-09-2011, 12:15 PM
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knock at engine sprocket end when shutting throttle in gear
Hi again and many thanks for the tips so far.
I've removed the sprocket cover, checked the chain and both sprockets - everything ok there although I have noticed a couple of millimetres play in the engine end sprocket moving on the shaft even though the sprocket nut is tight.
I wonder if when running, this couple of millimetres play is amplified, manifesting itself as a knock given the power that the engine delivers or is the play I've found normal?
Again, thanks in anticipation.
I've removed the sprocket cover, checked the chain and both sprockets - everything ok there although I have noticed a couple of millimetres play in the engine end sprocket moving on the shaft even though the sprocket nut is tight.
I wonder if when running, this couple of millimetres play is amplified, manifesting itself as a knock given the power that the engine delivers or is the play I've found normal?
Again, thanks in anticipation.
#9
09-09-2011, 01:12 PM
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My location
Thanks for your input Hawkwind.
Its a good idea that I let people know where I am of course so here we go....
I'm in a town called Swadlincote, South Derbyshire, UK. The English Midlands as its known here. Between Ashby de la Zouch and Burton on Trent (a brewery town) which comes in useful!!
Been riding bikes since I was old enough to and now a born again biker of 54 years. Originally from the North East - Newcastle - a 'Geordie' and proud of it!
Its a good idea that I let people know where I am of course so here we go....
I'm in a town called Swadlincote, South Derbyshire, UK. The English Midlands as its known here. Between Ashby de la Zouch and Burton on Trent (a brewery town) which comes in useful!!
Been riding bikes since I was old enough to and now a born again biker of 54 years. Originally from the North East - Newcastle - a 'Geordie' and proud of it!
#10
09-09-2011, 01:19 PM
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Hi again CBRclassic
I've checked the Chain and the sprockets both look ok for wear - no 'hooking' on either. The chain is in pretty good order too, no tight spots and a good fit on the sprockets.
I've just removed the back wheel and found that the sprocket turns about 5-10mm in the cush drive hub.
Maybe that's the problem?
I've checked the Chain and the sprockets both look ok for wear - no 'hooking' on either. The chain is in pretty good order too, no tight spots and a good fit on the sprockets.
I've just removed the back wheel and found that the sprocket turns about 5-10mm in the cush drive hub.
Maybe that's the problem?