Engine Rattle?

[lihp]

So vital info

Bike: 2002 R6
Mileage: 37k Miles

So here we go,

Now the bike has always had the, a slight tinkle like many Yamaha engines, but has started to develop a slight vibration going through 4k RPM.

Fast forward to riding home from work today, I was in a 30mph at around 5k rpm as I had an Audi up my arse, as it went into the NSL I accelerated quite briskly to my horror a very loud rattle started, sounded like very severe cam chain rattle.

I pulled over at some services and when below about 2k rpm the sound is not there, but as the revs pick up the rattle becomes more severe and very loud.

After it idling for 10 to 15 minutes the sound reduced and had now gone by the time I set out to finish the remainder of my journey.

The sound was varying with engine revs regardless of load, and did not vary in relation to road noise.

I've heard some and this sounds similar to a failed CCT, however, this is usually poor at idle and quieter as engine speed increases.

I found these videos to try and help, it did for a short while sound similar to this

https://www.youtube.com/watch?v=XOoTkm_zNw0&feature=related

But possibly only as bad as this one

https://www.youtube.com/watch?v=ojxOHeW1m4w&feature=player_embedded

Difference being, is that my rattle went away at idle and came as revs increased beyond 4k.

I'm really hoping it's not an engine bearing but it seems to be pointing that way. However, if it is a bearing, surely the noise would always be there at that RPM under the same circumstances surely? Is it possible for bearing to fail then for the noise to go less than 30 minutes later?

I have not noticed any change in engine performance, nor have I noticed any change in the engine characteristics.

Many thanks for reading

[Budgetboy]

Does sound like a spun bearing (IMO).. If the CCT was naff it would do it from idle as well..
As you hit the gas you put the engine under load.So everything is under more strain.
If i was you i would check the valve clearances to rule these out.
Reset the CCT and then see what you get.

If it still happens id say bearing.

Do you change the oil regular?
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[DrDonnyBrago]

[lihp]

oil is changed every 6 to 8 weeks, which works out about every 2000 miles or so.

here is what I've found now so far.

No signs of metal damage in the oil, nor in the trigger wheel cover.

I will remove oil filter and strainer tomorrow.

Upon inspecting CCT it did appear to work correctly (on the R6 it's a spring not oil pressure)

However, when I retracted it fully it locked in place, until twisted a bit on the mechanism at the back.

Yamaha service manual states, that to install one you need to screw the back to retract the piston, then keep screwdriver in whilst you install it. It was possible for me to put it back without doing so as it stayed in place fully retracted.

This may explain why the noise has now disappeared, if under my acceleration the tensioner retracted and locked, and then over time of idling it has released again, reapplying tension back onto the timing chain. This is my thoughts at the moment.

And I'm going to look for a new CCT possibly a manual one to rule out all together.

[DrDonnyBrago]

[Suntan Sid]

If you suspect it's your CCT, just replace the original, automatic, one with a Manual CCT.
I did it on one of my bikes, it took about 20 minutes, most of the time was taken up because it was in an awkward place.
A quick look at an R6 forum, reveals that you will have to block off the oil feed with some silicone, allow that to dry, then carry on with the installation.
Once you've installed the MCCT, and tensioned it correctly, you can forget about it until your next service.
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[lihp]

I've ordered a manual tensioner. No oil feed on mine as its not a hydraulic one, thanks for info though guys!

[Budgetboy]

There you g o then.. CCT. These stick on old honda's but if you whip em out and reset them they work again,but i always advise to get a manual one.
I would say once you install it you will be ok.
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