Exhaust joint blowing

[Harris Tweed]

I've got a stainless 4-into-1 that's blowing at the joint where the back pipe (and can) meet the collector box/joint of the front section. I separated the sections, both looked in good order though one end had flakes of rust, I cleaned both ends and re-sealed with exhaust paste. The joint seems to always last for a week or so and then it starts blowing again. I've tried exhaust paste and epoxy resin but the story is the same. I've heard that high-temp silicone sealant is the way to go on stainless due to expansion? Any advice?
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KH125Ex-L1 (1984). Past: GSX750, BMW F650; ER500; GN400; KH125Ex-L1 (again).

[Casper]

I use this

https://reviews.halfords.com/4028/741520/reviews.htm

Dries hard and not blown out yet.

[Walloper]

it sounds like the joint mating is out.
The can should slip over the downpipe.
It should be a tight to awkward slip.
Maybe the pipe is worn so you may need to re-work the can by making the splits a little wider so the part of the joint that is the can is able to squeeze a little tighter.
Gun Gum etc. is to exhausts as gaffa tape is to bodywork repair.

If you do not want to cut your can then use a steel can to wrap around the pipe and increase it's diameter slightly to get the tight metal to metal fit.
The tight fit gives the gas-tight seal.
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W-ireless A-rtificial L-ifeform L-imited to O-bservation P-eacekeeping and E-fficient R-epair

[Fizzer Thou]

If the fitting between the silencer and the downpipes is not a slip fit it might need one of these

https://www.mandp.co.uk/productinfo/524831/Exhausts/Exhaust-Gaskets/On-Two-Wheels
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Just talk bikes.What else is there?

Always have a 'Plan B'

[Harris Tweed]

Thanks for the replies, I think you are right, the joint has worn and will probably need a seal and some better sealant. Thanks for the www links too, much appreciated.
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KH125Ex-L1 (1984). Past: GSX750, BMW F650; ER500; GN400; KH125Ex-L1 (again).

[Bezzer]

When you say GSX750W do you mean the GSX750 FW Teapot??. If so Suzuki use a large diameter composite gasket to join the collector to the link pipe on most of the oil cooled motors including the Teapot, if thats gone then it's hard to seal it as stuff keeps getting blown out.
Have you still got a clamp on the joint?? if not that's your main problem the mild steel collar has rotted away same as you get on Bandits. It need cleaning up and a replacement collar in stainless welding in to make it as good as new again. Otherwise you're looking at a new exhaust.
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I used to be indecisive but now I'm not quite so sure.

[stinkwheel]

Clear bathroom silicone from B&Q for exhausts. Doesn't need to be anything fancy.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Walloper]

https://www.screwfix.com/p/dow-corning-flue-silicone-red/31593;jsessionid=zQ0jTKFTwQdS52yFVVhr0drR41JThZGYQ0GwH1vyN9NynQvp4PVs!484978413

Screwfix are not (always) cheap BTW.

B&Q will take about the same for their cheap own label bathroom sealant.

https://www.diy.com/diy/jsp/bq/nav.jsp?action=detail&fh_secondid=11348631&fh_location=//catalog01/en_GB/categories%3C{9372013}/categories%3C{9372031}/categories%3C{9372100}/specificationsProductType=sealants
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W-ireless A-rtificial L-ifeform L-imited to O-bservation P-eacekeeping and E-fficient R-epair

[Harris Tweed]

[kingsmith]

[Dazbo666]

[Bezzer]

[Dazbo666]

[Harris Tweed]

Located a gasket/collar which is on the way. I think I'll try a spot of silicone too but I can't believe the standard B&Q stuff will do the trick though!
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KH125Ex-L1 (1984). Past: GSX750, BMW F650; ER500; GN400; KH125Ex-L1 (again).

[jimster]

This is a "holy thread resurrection Batman" moment so apologies but I want to try the B&Q sealant trick on my exhaust to prevent it leaking.

I know nothing about bathroom sealant but I went to B&Q and they had "interior bathroom clear silicone sealant" and "interior & exterior clear silicone sealant". Which is better please? I got both just in case but would prefer to use the optimum product from the start

It was about £3 a tube by the way so very affordable!
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Current: Yamaha Diversion XJ900
Previous: Yamaha Diversion 600cc, Piaggio Zip 50cc, Honda CG125-W, Siamoto Caddy 50cc moped

[stinkwheel]

I'd probably go with the outdoor stuff.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[jimster]

Thanks Stinkwheel and welcome back to this thread after a decade away. It is the better for your return
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Current: Yamaha Diversion XJ900
Previous: Yamaha Diversion 600cc, Piaggio Zip 50cc, Honda CG125-W, Siamoto Caddy 50cc moped

[stinkwheel]

In honesty, I just use whatever's in the shed and isn't totally fossilised in the tube but I'd imagine outdoor stuff will have some sort of UV protectant in it.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[jimster]

[MCN]

The outdoor or indoor sealant won't last for as long as this thread. That's a given.
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Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN.

[stinkwheel]

I've used silicone sealant of the exhaust header of an air-cooled bike before today. It's also sealing the flue of my wood burning stove.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[MCN]

Some are good up to 300° Centipede.
AGA/Rayburn stoves use a high temp sillycunt sealant (from 3m) to glue the SS rope seal into the edge of the hotplate covers.
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Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN.

[Pete.]

If you can find it, get some flue sealant.
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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