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Discussion Starter #1
On my '03 with 26,000 miles I'm getting quit a bit of rattle noise from the engine at idle, seems to be more on the right side up in the top end, and goes away or can't hear it above 1,750 rpms. I'm either thinking valve shim adjustment or tensioner. Has anyone experienced this noise before and what was your problem? Thanks.
 

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My 04 had a idle rattle and so does my 2012 its my opinion all do it to some extent. Some may be worse than others.
 

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Discussion Starter #3
It just sounds a lot louder than it should be. It's certainly very noticeable now with the new adapter making the CVT end quiet.
 
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There may be nothing wrong at all but my guess would be timing chain/guide.
 

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My 08 is very quiet.
 

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Discussion Starter #6
My '09 is pretty quiet and Dave Hobin's '07 I just worked on. It's actually more like a clacking noise right side, area by the tensioner, hmmm.
 

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Discussion Starter #7
Here's what I found when I pulled the valve cover off and spark plugs out to check valve clearance. I rotated the motor around with a socket and ratchet.

A normal properly tensioned timing chain



A normal tensioner applying tension to the timing chain



A not normally tensioned timing chain



A not normal tensioner unloading and not keeping the timing chain properly tensioned



So it's as I suspected, a problem with the tensioner. Bascially the tensioner was unloading at times and allowing slack in the chain. This caused either the chain or the tensioned part of the chain guide hitting it's stop which made the clacking noise I heard. The tensioner has a pawl/ratchet mechanism that should not allow the tensioner to fully unload like it is doing on my '03. Others who have played with the valve adjustments can attest to having to unlock the pawl on the ratchet (special tool or wedging something in to hold the ratchet pawl back) on the tensioner before you can pull the chain off the cams. So looks like the pawl, shaft, or pawl lock spring for the tensioner is bad so I'll be replacing the tensioner soon.
 
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Thanks for posting this.
Can you explain how you can tell the tensioner is defective just by looking at it (The tensioner itself not how the chain is laying - just for my education ). :thumbup:
 

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Discussion Starter #9
NormanB said:
Thanks for posting this.
Can you explain how you can tell the tensioner is defective just by looking at it (The tensioner itself not how the chain is laying - just for my education ). :thumbup:
Sure. The tensioner pulls down on the upper timing chain guide to tension the chain. The tensioner has a one way ratchet built in. When the chain has slack the tensioner tightens the chain and the ratchet holds it from coming loose. As I turn the crankshaft and the chain rotates it should not get loose like it was doing. In the two photos of just the tensioner you can see the shaft had moved up making the spring shorter. This you can see in the distance between the head bolt behind it and the spring end of the tensioner.

I came home tonight and since I already placed an order for a new tensioner I decided to pull the old one out and take it apart to see what I would find. Sure enough as you'll see below in the photos the teeth on the shaft and pawl are worn. Basically it looks like if the shaft vibrates causing it to twist it then put the load on the worn section which in turn slipped causing it to unload. When it unloaded the upper timing chain guide would then flip up hitting the case inside making the clack noise I could hear. On to the photos.

Timing chain tensioner disassembled



A closer view



A closeup of the shaft showing one side has tooth wear.



A closeup of the damage to the pawl

 
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Thanks for this one. Great Pics.

I learned something.
 

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Thanks for the explain. :)
The critical failure seems to be that the load was not being carried across the full width of the pawl and was instead cock eyed and creating a point load rather than an even load across the full width of the pawl. As a consequence the wear on the pawl is much more severe than that of the tensioner shaft.
Do you agree?
If so what has caused the pawl to sit cock eyed to the axis of the shaft, I can only assume it was not an assembly error.
 

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Discussion Starter #13
NormanB said:
Thanks for the explain. :)
The critical failure seems to be that the load was not being carried across the full width of the pawl amd was instead cock eyed and creating a point load rather than an even load across the full width of the pawl. As a consequence the wear on the pawl is much more severe than that of the tensioner shaft.
Do you agree?
If so what has caused the pawl to sit cock eyed to the axis of the shaft, I can only assume it was not an assembly error.
The problem seems to me that the shaft which is held in by a roll pin (out of view in the photos) which allows some twisting play in the shaft and that as happened it loaded one side of the pawl which couldn't handle it (like you said) . I'm assuming normal movement/vibration was moving the shaft, then the would pawl slip, and then it unloaded the chain guide slapping it against the case. This happened as the cams came up on their lobe which puts the load on the tensioner.
 

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MJR maybe a drill and ream job with a new solid pin to fit more snugly is a worthwhile preassembly modification?
 

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Discussion Starter #16
NormanB said:
MJR maybe a drill and ream job with a new solid pin to fit more snugly is a worthwhile preassembly modification?
Was thinking that drilling and adding a slightly larger pin might be wise but it's the same tensioner on all these bikes and only had a couple of failures from what I know. I got a new one coming and I'll have to see how the new one is.
 

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looks like i may have the same prob fitted my polish shaft today hoping that it would stop my engine noise on tickover it has made it better but there is still something going on in there so think it maybe tensioner or chain mjr are you going to fit a new chain or just the tensioner will have to price up the bits i need
 

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Discussion Starter #18
joe 90 said:
looks like i may have the same prob fitted my polish shaft today hoping that it would stop my engine noise on tickover it has made it better but there is still something going on in there so think it maybe tensioner or chain mjr are you going to fit a new chain or just the tensioner will have to price up the bits i need
So it sounds like a clacking noise at idle and goes away off idle? Pulling the crank bolt cover and rotating the engine clockwise by hand with a socket/ratchet you should be able to see if it does the same (hear/feel) as mine. I see no need to change the chain since the teNsioner rides in the middle so the chain is not stretched.

I found that the rool pin holding the shaft in and which is suppose to keep the twisting to a minimum doesn't go through the shaft but butts up against a machined flat spot on the shaft. Either it was made poorly with the roll pin not pushed in all the way, it backed out over time/mileage, or it wore the roll pin (shaft looks ok but I'll probably take that apart to see and photograph).
 

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Discussion Starter #20
So here's the photos of the roll pin and bits that are suppose to retain and restrain the shaft. Looks like either it backed out (was only slightly sticking out about a fingernail thick, the photo below is after I pushed it out all the way and not how it came out of the bike) or wasn't in all the way from the start. There is some minor wear on the end of the roll pin where it is against the shaft. It can apart real easy which doesn't give me a good feeling. I noticed that the pin is pressed in on the outside (toward the open part of the timing case vs. being between the tensioner and timing case where it mounts. A thought is tapping and using a set screw with loctite but I'll have to see what the new one looks like before I can decide about mods.

Photo below is after I pushed the roll pin out all the way and not how it came out of the bike.



Small length of the roll pin and slight wear at the tapered tip.

 
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