Ok, so I got an exhast leak - it's actually a very thin crack in the pipe where the aftercan is welded (see the picture - I know it's not the best quality).



To weld over the crack, I'd have to take the exaust off.  With the infamous allen bolts that hold the exhaust to the engine, I'm a bit causious even touching them.  So my question is: can I use metal epoxy on this crack?  I have the high-pressure, high-temperature metal epoxy that claim to withstand 150+ degrees celsius - would that work?

As always, thanks in advance.

Forget the epoxy metal. Some gun-gum from Halfrauds will seal it, just slap it on and paint it black when it dries, or try a repair bandage. But the only way to restore its integrity will be to weld or braize the crack. It might be possible to do it in situ without removing the exhaust from the bike if you can find someone willing to give it a go.

http://www.holtsauto.com/products/group/repair-and-maintenance/exhaust-repair

Surprised you got an MOT with an exhaust in that condition, it looks to be cracked at least half way round. Did they give you an advisory or did they miss it altogether?

They did give an advisory - this is how I actually learned about it.  Somehow, when checking the bike around, I never really looked at the exhaust.  As there is no excessive noise, I didn't have to look for the source.  Well, now I know.

As for welding it in situ, I have asked a couple of places that do welding - and both said that'd have to remove the exhaust.  There's one more place that I'll ask - the guy that welded my front sprocket onto the shaft with no teeths (I did write about it in a separate thread) - maybe he'll agree to weld it.