Rattle on a Bandit 400. Please help!

[tommmd]

Hi all

I have a rattle on my Bandit 400. It starts around 3000RPM up to 6000 or so. It's a horrible noise, like a metallic clacking sound or like a heat shield banging on an exhaust (it's pretty loud).

It's not there when you start the bike cold, comes on after a minute or so and then tends to disappear once it's warm. Sounds generally like it's coming from the top of the engine/under the tank. I can't find anything loose under the tank, any idea what it could be? The bike runs fine on all 4 cylinders.

Any help much appreciated as I've run out of ideas!
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Tom

[ADSrox0r]

Loose cam chain *, inspect tensioners and replace.

* Opinion, not fact.
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Current bikes: '08 VFR 800 VTEC(yo) , '07 ZZR1400 Winter hack: '95 Aprilia 650 Pegaso Currently lusting after: RC30

[RhynoCZ]

I do not think it's the cam chain, as that would make noise the other way around, meaning you rev it at 6000 rpm, then let go of the throttle and the chain whips something in the engine. If the chain was loose enough, you'd hear it at idle.

Your noise issue may be elsewhere. Have you check the exhaust headers? Anything loose there?

Anyway, if your motorcycle is equiped with the factory automaticly adjusted tensioner, then you may reset it, without removing it.
HOW? - Screw driver in the slot in the tensioner (from the outside), turn it clockwise (that will lessen the tension) and then let go. There is a spring inside the tensioner that should push the rod of the tensioner back to its original position, giving you the perfect cam chain tension. If nothing of that happens, THEN replace the tensioner.

You may also make sure the chain is tight enough, if remove the valve cover (easy job, no special tools required). You'll be able to tell right away, if the cam chain is too lose. Which should not be neccessary, if the tensioner works as it should.

People often change parts, that only need resetting and adjusting.

EDIT: When was the last time you changed the oil?
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'87 Honda XBR 500, '96 Kawasaki ZX7R P1, '90 Honda CB-1, '88 Kawasaki GPz550, MZ 150 ETZ
'95 Mercedes-Benz w202 C200 CGI, '98 Mercedes-Benz w210 E200 Kompressor

[haroman666]

Is it the VVT engine?
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The mistresses: 2000 Honda CBR600f, 2000 Honda VTR1000

[pudder]

Might sound stupid, but check rear footpegs.

It's not uncommon for the up position detent spring to become weak, and the footpeg to rattle.
Makes a nasty noise.

Worth 30 seconds to check.
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1993 Kawasaki AR50 (In bits) - 1984 Suzuki GP125 (Sold, but still ridden) - 1954 Matchless G3L (Being restored) - 2007 Suzuki Bandit 650

[tommmd]

Thanks for the advice, everyone. No it's not the VVT and oil changed around 500 miles ago. I'll try to attach a video. It's a horrible noise, but it isn't there at idle and goes away when the bike is warm. The bike otherwise runs well.

Wasn't the footpegs but thanks for the suggestion! I'll have a go at resetting the cam chain tensioner in the morning, getting a bit late and I've annoyed the neighbours enough for now.

Would a chain tensioner make more of a clicking noise rather than a rattle? Have had one go on its way out on my car and sounded different to this.

Thanks everyone, appreciate the help.
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Tom

[tommmd]

https://drive.google.com/open?id=0B6fiu6wg--MkdV9rNTYtYmRNVGc
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Tom

[haroman666]

Loose cam chains normally have a "chatter" sound to them, if you can imagine that sort of noise.

I find when searching for a mystical noise, it's best to work methodically from the crank shaft all the way to the back wheel (via everything in between), considering what rotates, what slides, what interacts etc etc just to have a vaguely linear route of searching.
This is instead of having a chaotic "Ooh i'll check that." ... "OOH i'll check that over there too." etc etc
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The mistresses: 2000 Honda CBR600f, 2000 Honda VTR1000

[tommmd]

Rhyno, just did what you suggested. It springs back into place but the noise is still there when I started it up again. Hopefully the video helps?
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Tom

[Pete.]

Bash the exhaust headers about with a rubber mallet or something similar. Odds on that one is loose or rotted at the exhaust port. It makes a clacking noise similar to big-ends knocking.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[bypass2]

did it make the noise before you did the oil change. did you change the oil filter as well if it has one.

[tommmd]

Hi all, it is the cam chain tensioner causing the noise. Tightening the screw a little makes it go away. Will have to replace that now.

Thanks everyone! Fantastic advice all round. Really appreciate it.
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Tom

[RhynoCZ]

[haroman666]

[RhynoCZ]

[tommmd]

Followed all orders as instructed I promise.
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Tom

[tommmd]

To anyone who helpfully posted or anyone who sees this in future:

I took the tensioner out and had a fiddle with it, cleaned it up with some WD40, dried and then clean engine oil and now it is working absolutely fine. I would recommend trying this as you can also gauge whether it's at the end of its adjustment (if it is you definitely need a new cam chain) when you put it back in.

Mine fortunately still had 10mm or so of adjustment and operates a lot more smoothly now.

Cheers
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Tom