Honda CBF 125 rattle - inner exhaust pipe

[rich666]

Hello peeps!

Just bought a nice little CBF125, after running it in the garage I noticed a rattle at 4K upwards.

Fearing the worst I had a good listen close to the engine and it did sound a little like something near the exhaust downpipe.

So I have just whipped the pipe off and found that there is an inner pipe which appears to have sheared off right at the start of the downpipe?

I am assuming it's not supposed to be rattling about!

It looks a bit of a challenge to weld back on unless I cut the whole pipe through first then weld the whole lot back together.

So I can either ignore it, look for a replacement used original or just get an aftermarket system.

Any other ideas? Is this a common fault?

The bike is pretty mint otherwise and only has 7500 on it.

Any ideas welcome!


(EDIT) There's a pretty clean system on ebay for under 40 quid but the seller says it's NOT for injected bikes??? Aren't all CBF's injected?

[Snod Blatter]

I believe the CBF125 was also sold in India (or other markets, anyway) where it was equipped with a carburettor instead of injection.

Anyway, the inner pipe breaking free seems to happen any time an inner pipe is used. There is no magic fix, not being able to weld I just ignore it
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1994 CB250, 1984 CBX250RS-E, 1989 K100RS, 1995 TRX850, 2016 Z250SL

[BusterGonads]

My son recently had his mint CBF125 bike stolen and bought another one. After about three weeks this horrible exhaust rattle thing happened to the one he bought; a sub 5000 mile one. It makes a hell of a noise at about 5k 6k which is a nuisance because it spends a fair bit of time around those revs. He's thinking of looking for a second hand system on Ebay, but of course it might happen again.

EDIT: I saw that ebay exhaust that is marked 'not for injected bikes' and thought the same. These are all injected.
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2023 Royal Enfield Classic 350; 2000 Honda CG125; 1997 Honda Nighthawk CB250

[rich666]

Just got another system off ebay, £30 posted, pretty cheap.

Not quite as good nick on the outside as the broken one but it will do.

I'm going to cut the broken one open and weld it back together.

I think the heat from the exhaust gases so close to the cylinder make the steel brittle and it's fractures due to expanding and contracting.

[BusterGonads]