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Discussion Starter #1
I have a question..

My 95 cbr900 has a very clear and loud 'clattering' type noise when under load between about 2900-4500rpm...kind of like there is a ball bearing rattling around in there somewhere...
I have adjusted the needles to make it run richer, which has resulted in poor low range performance, and hesitation, but good acceleration above 4000rpm. However the noise is still there.
So my question is:

Would the noise be jetting causing a lean 'knock'?

Or could the Cam chain tensioner cause this?
I ask because i know the tensioners can be dodgy, but i dont know the symptoms of a dodgy one?
the bike makes a very slight noise when idling, but its more of a whirring noise, and not a knock. it doesnt seem to make the clattering noise when i rev it in neutral, only when under load.

So could this be the tensioner, or should i look other places for a fix??
 

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I bet its the tensioner. Does the sound go away when the bike is warm?
 

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Discussion Starter #3
NOPE...
it is maybe a little more obvious when cold, but its still there and loud when warm.
I got a new cam chain installed recently, and the mechanic did tell me that the only thing that may need replacing in the future is the tensioner, but never said it was bad.
He has also ridden the bike twice, and says he cannot get it to 'knock' or 'ping' under load.
Maybe he is hearing the noise, and not taking any notice of it, knowing its the tensioner.
But i thought the tensioner was only noisy when cold, and made a whirring noise anyway. this is just like a ball bearing in a jar being shaken vigorously, and it only happens obviously between 2900-4500rpm and while under load, not in neutral.
I would have thought the tensioner would make the noise all the time, through any rev range??
 

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I had an '89 CBR1000F that had a prominant "rattling" sound. Sometimes when cold, sometimes warmed up. Sometimes went away, sometimes stuck around. Several shop techs agreed it was the timing chain tensioner. I was told that in order to replace it, the engine would have to be flipped and the case split. They also agreed (to my dismay) that it was causing NO harm to the bike :idunno: So I rode it like that for years before selling it. That was the last time I'll own an in-line four though :rant:
Clay
 

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Discussion Starter #5
Mine is there all the time, without fail, and at exactly the same rev range, everytime without fail.
I have to admit, with the loud pipe, its hard to hear if its there above 5000rpm, but i dont think it is....

Anyway, mine is also easy to change if required, but i really would like to know if the cam chain tensioner would make a noise like this, only when under load, and only at certain revs before i spend any monies on it.
 

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Replace the cam chain tensioner. They are notorious for going out on the 900RR and F2/F3 bikes. They are also cheap and take all of a half hour to replace - even if you are completely mechanically incompetent. Very very simple install job.
 

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BDA116 said:
Replace the cam chain tensioner. They are notorious for going out on the 900RR and F2/F3 bikes. They are also cheap and take all of a half hour to replace - even if you are completely mechanically incompetent. Very very simple install job.
Yup, odds are it is the CCT and since it's a cheap fix so go ahead and pull the trigger.

I will say that the one on my F3 went bad at about 20,000 miles and it began to make a noise that would go away at certain RPM and when the motor was warm. I replaced it with an Orient Express CCT for ~$80 .

Good Luck!
 

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Discussion Starter #8
ok then, i will go and do that this weekend...
but im still not convinced guys, sorry.
if the sound went away i would believe it, but this is there all the time, warm or cold, and only at a very specific rev range.
but, as you said, the CCT is not expensive, so well worth a shot for the time and money, and of course, peace of mind...
 

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Ya know, I have a 95 900RR aswell, that too is making that ticking noise. Many have told me its the LEAN mix, aswell as my exaust gaskets are bad and what Im hearing is the exaust valves open and closing... I have a Full two brothers exaust and slip on the bike. at about 3k-4k you can start hearing it and when you nail the throttle you can really hear it. Without a helmet it sounds bad, but people tell me they cant hear it over the exaust. I thought it was just me, but a buddies bike '98 900RR' did the same. So i guess I am going to go look at the CCT. and see if that needs replaced even though my chain feels fine, and when replacing a cam chain, you dont have to crack open the crankcase. Im a cycle tech and I have done a couple without opening it. its totally easy to replace aswell.. just the chain isnt cheap...

Archer
 

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Discussion Starter #10
I have already had the valve clearances adjusted, and it has a new cam chain about 200km ago., but the mech did tell me then, that the CCT would need replacement soon, i should have just had it all done then.
I will get one next week, and i will let you know how it goes..

AS an update, i thought mine was running LEAN on the jetting too, so i adjusted the needle clip to richen it.
Now it is so rich that you have to ride the clutch to take off and it coughs and splutters under 3000 rpm. but the noise is still there badder than ever.
So i am thinking the CCT may well be the cause, and for $70 I figure, why not go and do it...
 

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I know on the 900 the slides have a certain tolerance to cope with expansion due to heat. Apparantly this results in the slides rattling inside the carbs. Its most noticeable when cold but obviously diminshes when they expand, however its allways present. There has been lots of cases of new CCTs and rebuilds done to find this was creating the noise all along. Suprisingly the slides show no sign of wear due to this, according to Honda?
 

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This I understand, however, what I dont understand is that I am having a noise. a ticking or a clank. Its not the pistons, nor the valves. I think I may have to adjust them with shims, but I only have 10k on my motor. I wouldnt imagine it would be the CCT. besides, it only gets louder around 2k-4kRPM. it doesnt go away when it gets warm... sound pretty much stays the same as the RPMS go up. So Im thinking im running lean, carbon deposits, and valve adjustment. Well, i have my work cut out for me this winter huh. lol

Archer
 

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Discussion Starter #13
how loud would the slides be???
this almost makes sense to me, as they only do it with the throttle open.
at the rev range where it rattles, if i back off the throttle just slightly, the noise dissappears, then when i roll it back on, the noise starts again.
i had the needles adjusted rich, and the bike was stuttering and horrid to ride because it was obviously too rich in the low range, but the noise was still there. so this weekend, i adjusted the needles back to where they were. now its very smooth and nice to ride with decent power, but still has the horrid noise.
for $70 i am gonna replace the CCT anyway, but then if the noise is still there, i will look into the slides.

Let me know how you go if you find your problem too Archer...
 

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goforitifudare said:
how loud would the slides be???
this almost makes sense to me, as they only do it with the throttle open.
at the rev range where it rattles, if i back off the throttle just slightly, the noise dissappears, then when i roll it back on, the noise starts again.
i had the needles adjusted rich, and the bike was stuttering and horrid to ride because it was obviously too rich in the low range, but the noise was still there. so this weekend, i adjusted the needles back to where they were. now its very smooth and nice to ride with decent power, but still has the horrid noise.
for $70 i am gonna replace the CCT anyway, but then if the noise is still there, i will look into the slides.

Let me know how you go if you find your problem too Archer...
I'd be really interested to find out how u go. Slides is the theory over here for the noise but you know what they say about theories! Let me know dude
 

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Discussion Starter #15
The mechanic who did the Cam chain about 300km ago did tell me that in the future the only thing that will need replacement will be the CCT, but he never mentioned that it was so bad now, which does make me wonder a bit.

but as i said, for the price, i may as well replace it anyway.

I will let you know how i go with it.
 

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Discussion Starter #17
I replaced mine with a Manual adjustable one.
i had it all adjusted properly, and the noise was still ever present.
the bike had a dyno run, and carbs adjusted.
so i knew for sure it wasnt the CCT, and i also knew for sure it wasnt running lean.

at the end of the day, i put up with it, as the mechanic couldnt fault anything, and the two obvious suspects were repaired.

i kept it for another 6 months or so, with no problems whatsoever, before i sold the bike. i still see it around, so its obviously still going strong.
 

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Thanks for the reply it saves me going to the effort and expense of doing it myself.:thumb:
I am still curious so I'm hoping someone will come up with an answer.
 
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