Engine rattle

hellbound · World Chat Champion Joined: 15 Jan 2011 Karma :

ZX6R 1998

Doing 50ish this morning and all of a sudden I get a really loud rattle, pulling the clutch in makes no difference but for a minute I thought I had slipped out of gear as it sounded like that.

After 5000rpm it stops making the noise but under this its horrible.

Can't seem to distinguise which bit its coming from though.
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Frost · World Chat Champion Joined: 26 May 2004 Karma :

So i take it the rattle is due to engine speed rather than road speed? I.e does it do it when it's not moving? Does it do it in gear only?
If it's actually engine related you should be able to walk around the bike and hear where it's coming from. It might just be something loose. If it's coming from within the engine itself put a screw driver tip onto various parts of the engine with the handle at your ear and see if you can locate it.

I'd suspect the cam chain and have a look at the tensioner personally, though it's probably unlikely.
Also exhausts tend to rust then rattle when they start falling appart.

DrDonnyBrago · World Chat Champion Joined: 03 Jan 2010 Karma :

Sounds like a cam chain tensioner (CCT), see if it does it whilst revving on it's sidestand.

On your bike I think the cam chain runs on the RHS of the engine so the noise will be loudest on the RHS near the top if it is the CCT. When mine went it was noisy as hell at 5k, silent above it. Not sure on the design in your bike but the solution is either to clean it or replace it depending on why it has failed. Not a hard job if access is ok.

hellbound · World Chat Champion Joined: 15 Jan 2011 Karma :

It does it on side stand up to 5000rpm, just tried it. out of gear and pulling in clutch makes no difference.

And it is that side of the engine.

I am 30 miles away from home so i am hoping keeping it above 5000 will get me back.
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evoboy · World Chat Champion Joined: 20 Aug 2009 Karma :

How many miles has the bike covered?

The CCT's on Kwaks are normally a ratchet type that dont really need replacing, just cleaning and re setting.

Being a 98, i take it yours is a G model?
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hellbound · World Chat Champion Joined: 15 Jan 2011 Karma :

29000

And I believe it to be the G model due to the year

Sounds like a chain hitting something as its a constant LOUD rattle instead of irregular.
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evoboy · World Chat Champion Joined: 20 Aug 2009 Karma :

DrDonnyBrago · World Chat Champion Joined: 03 Jan 2010 Karma :

hellbound · World Chat Champion Joined: 15 Jan 2011 Karma :

I have taken CCT out and dismantled it to find the spring inside in two pieces.

now looking on how to get one asap but failing really well at that!

So I came back in and threw Karma about instead
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MarkJ · World Chat Champion Joined: 11 Apr 2006 Karma :

If you struggle to find a genuine CCT you could always make/buy a manual one Thumbs Up

https://forum.oldskoolsuzuki.info/yabb/Attachments/manual_cam.JPG

hellbound · World Chat Champion Joined: 15 Jan 2011 Karma :

Can't find one of them in the uk for now instead of 4 days

If I don't go into work tomorrow I am going to get a written warning (as confirmed by managment!)

Think he's annoyed that I took a week off begining of december when my dad died, I figured it was justified at the time!
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Frost · World Chat Champion Joined: 26 May 2004 Karma :

So the CCT is just a ratchet with a spring inside to move it along when the chain develops some slack. So why not find out the force of the spring, reset the tensioner and insert it, then apply the same force (roughly) as the spring would have done to move it along to whatever notch it should be at?
It's not a long term solution by any means but would be about the same as a manual one and would certainly get you to work and avoid getting fired?

If it's just the spring that's fucked find out the spec for it and buy one, it's just a bloody spring Razz

hellbound · World Chat Champion Joined: 15 Jan 2011 Karma :

I tried this, and it worked for about a mile.

then it slacked off again and went back to rattling.

Ordered a manual adjuster from debbens but doubt it will arrive tomorrow so i may have to bike in regardless on monday as I can't borrow neighbors car on monday.
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Frost · World Chat Champion Joined: 26 May 2004 Karma :

Take out the CCT and reset it.
Put it in and tighten it.
Take it out, as it has no spring in it it'll stay where it got tightened to. Count how many positions along it is / has left to move.
Put if back in a ride / run the bike till it rattles.
Take it out and see if it's moved.

If it hasn't moved then it might not be the CCT itself that's the problem. Considering it'll cost nothing to try but might let you know if you have more serious problems, i'd give it a go.

hellbound · World Chat Champion Joined: 15 Jan 2011 Karma :

but by winding it out and stopping the noise for a mile and then hearing a faint clatter that got louder in a minute or so would surely lead me to believe the CCT is fcuked?
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DrDonnyBrago · World Chat Champion Joined: 03 Jan 2010 Karma :

You are tempting an "I need a new engine" amount of destruction by continuing to use it with a knackered CCT. It might survive a bit of testing but it will cost considerably more than a taxi to work if it goes wrong.

If it lets the chain go too loose then the chain can skip on the cam shaft sprockets, throwing out your timing and letting your pistons and valves smash into each other. If you are particularly unlucky the valve can snap sending it bouncing around in your engine tearing shreds out of the cylinder until it gets hammered into your piston.

On the CBR, it is a screw thread held out by the spring, if yours keeps loosening then it might not rely entirely on a ratchet type mechanism, or one of the broken bits was the spring that held the ratchet tight.

Either way, it is tempting fate if it keeps loosening.

hellbound · World Chat Champion Joined: 15 Jan 2011 Karma :

I understand your point and I haven't been using it, it's sitting outside my house causing me to look at it with concern every time I step outside.
A manual tensioner is on it's way so hopefully Monday might I will be outside in the dark with a headtorch fitting it as my garage has no lights or power.
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