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corrosion on sparkplug housing

Discussion in 'Technical and Troubleshooting Torque' started by steve315, Feb 26, 2006.

  1. The situation: Overnight, rust started coming out of a moulded tunnel in the piston housing of my bike. The housing is Aluminium - so it shouldn't rust! I didn't cover the bike yesterday and the afternoon storms gave it a good soaking.

    Just behind the tunnel is where the sparkplug threads into the front cylinder, so I think that this is the source of ferrious metal. On the VTR250, water can pool around the bottom of the sparkplug recess on the leading cyclinder, and there was water pooled there this morning.

    The plugs were last removed last October for a 18,000 km service at Peter Stevens.

    If water is getting down the thread, what is coming up?

    The engine has been a bit rough - missing on one cyclinder - on starting until properly warmed up - could this have been the source?

    Is the tunnel to cool the sparkplug?

    Anyway, anyone got any advice? Take it to Peter Stevens? Or remove the sparkplug, try to clean the rust out, grease and reseat the sparkplug, and try some extra grease on the sparkplug seat?
  2. I know on my bike (and most others I looked at) the sparkplug recess is actually covered by a rubber plug which is part of the sparkplug lead - seems strange the VTR doesn't have this (is it missing or is it just a bad design). Anyway doubt the rust would be coming from the plug thread - more likely to be coming from the metal ring used for (un)screwing the plug. Take the plug out and have a look - if necessary replace it (plugs are cheap). If the corrosion gets to bad you might not be able to get the plug out :shock:. As for keeping the water out - regular soakings with CRC/WD40 might work to displace the water but you really need to find a way to stop it getting in there in the first place.
  3. thanks for the advice, JD

    I pulled the plug lead out - seemed to be in there pretty well - and there was a lot of grit and dirt. The tunnel actually seems to be a drain for the area under the lead, and a massive application of CRC through the tunnel blew the grit out.

    Then took the plug out, wiped the rust off it, gave it some more CRC, and put it back.

    Glad that it is not a case of water and rust getting into the thread. Have to make sure that the cover is on when it rains.
  4. Ahh CRC, is there anything it can't fix :LOL:. Good to hear the problem's fixed.