exhausting...

[andyjonc]

Hi everyone,

After a bit of advice please

I have bought a 2014 Sym Jet 4 125cc and had a flat rear tyre. Obviously to get wheel off I had to remove exhaust, and I have noticed it has a fair bit of rust. Not a problem, I thought, I'll just clean it up.

Then I noticed a small hole, as shown in the photo. Is this terminal or can it be ignored or fixed? Would like to save £££'s if possible!

Thanks in advance for any help,
Andy

[RhynoCZ]

What photo? Is the hole perfectly round and at the bottom of the silencer? If so, then it's the drain and it's supposed to be there.
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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

[andyjonc]

[RhynoCZ]

Yeah, that's not supposed to be there. Replace or repair.

At this point, start knocking around that place, more bits are gonna fall off, carry on until there is solid metal (nothing falling off), then weld a plate there. That's what I would do if I decided not to replace the exhaust. There are also some wrap solution/patch kits, but I just wouldn't.
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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

[Riejufixing]

[RhynoCZ]

I would also be tempted to just cut the old silencer off and mount a new one from a different machine. A used, small yet reasonable silencer.

Welding required, though. You could ask your local welder/car shop, if they would do it OR try to contact any of the BCF members in your area.
____________________
'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

[tom_e]

I want to know why the exhaust had to come off to get the back wheel out is that really how piss poor the design is?

[doggone]

Not that unusual, bad design really as you say, however it's usually only a couple of bolts - if done at least annually they should be easy enough to get free.

[Baffler186]

As suggested, you need to knock off as much of the rot as you can until you find solid metal, you'll likely have a bigger hole. As a quick fix you could try some metal gauze and chemical metal, even if you use 2 tubes it's only a few quid. Then sand off the outer surface so it's smooth. You could also repaint the whole thing with some cheap high temp rattle can paint.

Ive had success with this on small holes, but depends how big yours is. If it doesn't work, or doesn't last, you've only spent 10 or 15 quid
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Current: 2009 SV650 S, 1990 Kawasaki GT550
Previous: 2009 CBF125, 1998 GSF600, 2004 FZ6 Fazer, 1978 CB400a Hondamatic

[Grubscrew]

From the picture it looks pretty rot.
You could cut out the crap area and not the best repair patch with jubilee clips and a thin sheet of ally/ stainless steel and use some high temp sealant to seal it or better still get a breakers bike silencer.
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FJR1300/CBR1000F

[andyjonc]

got an update for you guys...

so i continued cleaning up the exhaust using a wire wheel on the drill. turns out there's another weak spot further around, but this much bigger, exposed the baffle material the exhaust is also blowing so will definitely need to be attended to.

i have looked extensively online and it seems that exhausts for this engine are VERY hard to get hold of. aftermarket options start at £200 which is way out of my budget!

so looking at other options, i have bought some gungum putty and exhaust wrap, with which i intend to cover the exposed hole and see if that does the job. the holes are at the back and bottom of the exhaust, and the wrap may not look very nice, but it is saves me £££ i ain't bothered.

i have also bought some kurust gel so apply to the whole exhaust to try to clean it up a bit. hopefully i will get this all done over the weekend so i will try to remember to post some photos next week!

cheers all,
andy

[ThatDippyTwat]

This stuff is better than fireputty/Gungum. I get 6 months between applications on the rat (similar exhaust problem - if available, it's stupidly expensive), not a week or two as with fireputty.

https://www.toolstation.com/fire-mate-intumescent-acrylic-sealant-310ml/p58145

Put underneath, flatten out steel "bean tins" and Jubilee clip them over it before it cures.
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'98 VFR800 (touring) - '12 VFR800 Crosrunner (Commuting) - '01 KDX220 (Big Green Antisocial Machine)

[Bhud]

You can't ignore it - it will fail an MOT, it will sound like a blowing exhaust and will negatively affect the running of the bike (depending on the hole's exact position).

You should get it welded. Welding will fix it permanently, whether it's by patching, fitting an inner pipe, replacing a bit of pipe, etc.

Don't be afraid to tap at it with something to remove all the rust and make the hole bigger. This will show you the extent of the problem, the thickness of any good metal you have left to play with, whether you could get away with just a couple of little beads over the top, etc. If the hole is REALLY small and the surrounding metal is good, you can seal it up without welding, by using a hand file to make it perfectly round, then screwing in a larger, brass, self-tapping screw (e.g. a wood screw). For a bigger hole with seriously weakened surrounding metal, that won't work.

Exhausts are expensive, it's true. But if you've got a blowing exhaust you have to either replace it, fix it permanently or temporarily (the jubilee clamps plus beans can fix looks bad but it will work for a while until you have to do it again).

[RhynoCZ]

Also, there is a very high possibility the insides (baffles) already rotten away, so what you've got there, even if you patch the hole/s, is more of a loundener rather than a silencer.

The best way would be really cutting it off and welding a new silencer there. Check the breakers, ebay... for anything suitable.
____________________
'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

[wr6133]

It looks like a Chinese GY6 clone

Any of these would probably fit
https://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=125cc+gy6+exhaust&_sacat=0