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Discussion Starter #1
Hi guys need some input here.
Did a full rebuild on my R6 a month ago
Have yet to complete the break in process.

Was riding when suddenly there is a rattling sound came out of nowhere and it will only appear above 4k rpm.

When the bike is on idle or anywhere below 4k rpm the rattle disappear. Below is the link

I pull my valve cover off and did some check on the clearance intake was in spec but exhaust was slightly tight so i swap those shims and get set the cleareance to 0.23 range hoping could be due to valvetrain issue or something as I also had difficulty starting the bike when engine is cold.
Had everything installed back i'm using manual cam chain tensiomer and set some freeplay on the chain as shown in the video.

So when i fire it up, that audible rattle was still there so i tried tightening the tensioner and the rattle starts to dissappear bit by bit. Will attach a video of it also.

Question is how tight should the chain be.
And could it be my chain was somehow stretched?
Is it really the chain causing the sound or could it be a spun bearing? Really hope someone could help me out here.
 

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That sound is the chain, you gave it a lot of tension, take a 1/4 out.

When I installed my APE tensioner it had that sound, indeed the chain is very tight.

You can also slacken with the engine running, but if you prefer, slacken with the engine off.

How many miles or kilometers does your bike have? If you have few, it is rare that the chain is already stretched, and possibly the camshaft tensioner is the culprit.

Regards.
 

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Discussion Starter #3
Hey thanks for the reply,
Bike had 55k miles on it.
But had a engine rebuilt a month ago due to a spun bearing.

Apparently the noise cameback the next day,
I'm not sure if it's really the sound of the chain.
 

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In the last video, I recognize that noise is that of the very tight chain, as I mentioned, remove the tension you can do with the engine running. You can do it safely, slowly release tension and check that the sound disappears, and tighten the locknut well. !!But you have to be careful, not to loosen too much and the chain jumps, and breaks something.!!!!



Here is an example, I no longer have my video, but it is the same noise.

What can happen is that your chain with those km is already stretched in some link, and the tensioner is not the culprit of the slack. And when you leave it in the correct tension it makes the rattle noise, and when you want to tighten it more to eliminate the noise of the account you give too much tension.

It would be similar to the transmission chain, there comes a point where you cannot tighten more, due to the stretched links.

Remove turns of your tensioner, if you cannot eliminate rattling and excessive tension sounds, your chain has to be replaced.
 

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Discussion Starter #5
Hi, i tried lossening the tensioner as you mention
Lossen and tighten accordingly but unfortunately the rattle sound is still there whenever i give it some gas. The rattle will only appear above 4k rpm. Anywhere below than that during idle,the bike sound as perfect as it is. My chains is only a month old. I dount its stretched unless i might have overtighten the first time assemble the engine. And bike is still breaking in from the new piston and rings etc.
Attach is a clip i took just now i muffled the exhaust so to get a better hearing on the rattling.
 

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Well, in the first video the rattle that is heard is apparently from the camshaft chain, since in the second video that you show you can clearly see the slack in the chain. In the third video you tightened the chain, right? When accelerating I do not hear the noise of the last video that you showed. As I mentioned the noise seems to me to be a very tight camshaft chain. But in the last video, it does not look like the first one, it sounds more like a sound in the crank bearings. But my questions are the following (sorry if you already proposed them before), to understand me better.

- In the first video you have the camshaft chain with slack as seen in the second video, is it true? The noise of the first video, for me it's the camshaft chain hitting

-In the third video, you tensioned the camshaft chain, right? Since that sound is very familiar to me, and it is due to excess tension. Is the noise of the last video heard when you accelerate with the chain tight?

- To finish in the last video that you showed, tighten the chain as in the third? But that noise doesn't seem to be chain, maybe it has those two errors.

Regards.
 

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This is exactly what my last dirtbike build sounded like .. not the same thing but it turned out to be a tooth off on the timing .. might be worth checking out after a full rebuild
 
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