Exhaust Blowing !!!!

[Yorick]

2017 Beta X-Trainer.

A while ago I had the exhaust header repaired as it had been bashed a few times on rocks and was squashed. They had to cut and weld it.
Now the bugger doesn't seal on the manifold and can see smoke blowing out and some black oil/goo dripping.
Can't wobble it, and springs are tight

Pal needs to borrow it tmrw, but I'm scared that it will run weak and seize !!

Any thoughts about running it 3 hours tomorrow ?

[Le_Fromage_Grande]

Put a second gasket between the header and the barrel.

I don't think it will do it any damage, it's a two stroke so not as sensitive to exhaust leaks as a four stroke, and if he's using it off road he'll hardly be revving it flat out for long periods.

You could always shove some Gun Gum or similar in the hole, but in my experience of two strokes the exhaust doesn't get hot enough for exhaust pastes to set

And it won't seize, it'll hole the piston if the mixture is too lean (or both if it gets mega hot)

[cheb]

High temperature silicon last surprisingly long when used on exhausts.

[Yorick]

Thanks for fix advice. Not got time to do it today, so will have to let him borrow it. He's paying (or his customer is) me 70€ for the day

[GuzziPaul]

High temperature silicon last surprisingly long when used on exhausts.

Seconded here for HT Silicon (I think most silicon sealant is HT). I've used it on my LC and DT two strokes in addition to a gasket. The LC always used to weep a bit of oil,but it stopped when I started using silicon. It also alows for a slight bit of movement between the engine and exhaust to damp out the vibration/movement between engine and exhaust mounts.

[cheb]

Low temp silicon will do too. By high temperature I mean the red stuff.

[GuzziPaul]

I just get mine from Toolstation silicon sealant for glass or round the bog/sink. Just been and looked Dowsil 785 https://cdn.aws.toolstation.com/items/coshh/27631.pdf
Much cheaper thana special automotive product which is the same thing in a smaller tube.

[Yorick]

Well, it survived 4 hours. His customers were novices, so just pottering along

[Yorick]

Individual gaskets were expensive so ordered a few

https://www.ebay.co.uk/itm/10-x-Exhaust ... 2749.l2649

When I took it all apart, I can see why they come in multiples as it needs 3 at a time. One between the end of the pipe and the barrel and 2 which go on the outside of the end of pipe like piston rings. The guys who repaired the exhaust only put 1 back in. And I think they bolted the whole thing into place then put on the springs. I did the springs first and made sure it was all in the right place, then tightened the mounting bolts without letting it move.

No more problems