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Installing full exhaust system - leaking

Discussion in 'Technical and Troubleshooting Torque' started by woodsy109, Sep 7, 2007.

  1. Is there a technique involved in the installation of an exhaust system?

    I've removed my Micron exhaust system to do some work, but once back on, I seemed to have developed a leak somewhere. Do you have to do some bolts up before others? I just positioned it in place and bolted them up as evenly as possible. I did notice that some bolts weren't very tight when I removed them so do they have to be tightened all the way or do they only have to be tight enough so the header is sitting inside the exhaust outlet? At the moment they all look like they are sitting in there nicely.

    I don't want to run it too much to find the leak as I don't know if this will damage anything, as well as the fact the exhaust will get hot so I can't work on it.

  2. You will have an air leak at the headers. Pull it all back off, and silicone the flanges. There is a heatproof silastic available for this.
  3. If you removed the headers, there is usually a gasket between the headers and the engine that you will probably need to replace.
  4. There is no actual gasket but they fit neatly into cylinder head and there are studs coming out from the block that you bolt the headers to. I think the silastic is probably the way to go. Although I didn't see any evidence of silastic when I removed them so not sure about how they were sealed before?
  5. Also what temps do exhausts get up to? I've got silastic 732 which says its good for 232C but i've a feeling that it might get higher than that.
  6. I've just read here
    that the steel header has a higher thermal expansion coeficient and so when heated, expands to seal the gap as the alluminium block has a lower coeficient and doesn't expand as much. Is it safe to run it for a while to test if heating the header will expand and seal it?
  7. Well the dark blue colour that the exhaust gets to is about 300C, if you can see a slight red glow at night thats about the 600c mark if it's a bright red that about 850c.

    Rather than just sloping silastic on (horrible bloody stuff used in the wrong aplication) i'd get a small tin of exhaust jointing compound, repco should stock it.
  8. Ok here are some photos. I just ran it for about a minute and then felt the header pipes and it is fairly evident that only cylinder 3 is leaking (3rd from left). Guess I will just pull it off again and try to re-align it.