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Heavy rain, engine pain.

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by Marmitemonkey, Jul 27, 2007.

  1. Riding home from a trip to Melb this evening, I got caught in a TORRENTIAL downpour, and I mean heavy - I could feel the impact of the rain drops through leathers.
    Pulled over to let impatient traffic pass as I couldn't see a thing and didn't want to push my luck on wet roads. After a pause of about 2 min I set off again, but the bike (CB250) started to splutter. Shortly after it decided to make 60 the top speed in 5th with the throttle full open. Pulled over again to see if sitting and turning over would help. Set off again, same prob, then it decided to cut out at about 40. Pulled over, and sat for ten mins, checked spark plug connections - rain passed. Started bike and after a bit more spluttering it ran normally.
    By the time I got home, the bugger was looking at me pretending it had never happened and that it was happy to do 100+.
    Am I right in guessing that the rain had forced water into areas that don't like water? It's never happened in the rain before, but this was really hammering down.
    Any tips or pointers would be appreciated.

  2. Sounds very likely.

    Some attention to ignition waterproofing may pay dividends.

    I always used to use vaseline, generously smeared on all spark plugs and around all ignition wire connections. It works but tends to melt and make a mess. Needs reapplying regularly.

    There may very well be other, superior products on the market.

    An extender or mudflap on the front guard can help too, by keeping spray from the front wheel away from the engine.
  3. Silicone grease is great Pat.
    It sounds to me that you still had partial power, so it is not likely to be a wiring problem up at the handlebars (this should have caused total failure).
    I'd say one of your coils is getting wet, or your spark plug boots is allowing water in, grounding out the spark plug.
    As Pat said, waterproofing is the go here, and check all connections for tightness and corrosion.
    My Z 650 would run like a top in heavy rain, even with one spark plug each side sticking out into the weather.

    Regards, Andrew.
  4. Finally had chance to look at spark plugs properly today. The cap/cover/boot on both spark plugs have dirty great cracks in them. Whacked some 100mph tape around them until I can get replacements, not that it rains much here.
    Thanks for the advice; soooooo much to learn.
    Am I right in thinking I can whip the electrical connections off and connect new cables/boots to the whole shebang?
  5. Yes you are correct. I woul replace the leads right back to the coils, cheap enough and easy to do. The coil leads usually screw in, so just start twisting them counterclockwise to remove from coils.

    Regards, Andrew.
  6. Cheers for the tips.
    Nipped out and got some used replacements, and stuck em on. Think I've replaced the coils as well if they are the bit the electrical connections clip to.
    Runs great, with less fear of rain delaying play.