999 Lack Of Power And Back Firing

Discussion in '749 / 999' started by ItchyRbuckle, Nov 4, 2019.

  1. Hi all
    I have a 2004 999s causing me some grief!
    When i start the bike after it resting a few hours it starts fine. I warm it up then set off, for a couple of minutes goes well...then it starts to lose power and constantly back fires. I have replaced the fuel relay cleaned the air filters. And now i am open to suggestions as i would like to try to fix myself before coughing large sums of dough

    Cheers steve
     
  2. What state are to coils in? And have the plugs been changed in its last service?
     
  3. I am not sure on state of coils but it had a big service about 5 months ago. I am a newbie so not even sure where the coils are...
     
  4. And as a 2004 bike are they the old style coils ie without a fly lead?
     
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  5. Okay, it would be worth removing them to check that you are getting a decent spark etc.

    They sit in the top of the cylinder head and push down on top of the spark plugs.

    This video shows them:


    Welcome btw :upyeah:
     
    #5 t3scn, Nov 4, 2019
    Last edited: Nov 4, 2019
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  6. Welcome to the Forum Steve.

    I’d take a look at the ignition system ie plugs & coils. Start by replacing the plugs with new ones then work back if that doesn’t fix it. It could be you have a plug that’s breaking down, the fault being exacerbated by heat hence it doesn’t do it until it’s warmed up. It’s not sparking properly thus leading to unburnt fuel in the exhaust thus leading to backfires.

    ps, introduce yourself in the Newbie section as well:upyeah:

    Edit : Snap ^^
     
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  7. Front coil connection will be corroded in the multi plug. You’ll need to replace the connector.
     
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  8. Wow, that’s a confident reply.
    I’ll be seriously impressed if you turn out to be right ;)
     
  9. Had the same issue with mine.
    Fires up fine. Idles great. Blip the throttle perfect. Two laps in, missfiring. Dropping on to one cylinder and backfiring due to in burn fuel in the exhaust. Fitted a spare coil I had. Still the same. Then cut the connection open to find a soggy green mess.
     
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  10. Coil on front cylinder is quite common, but i'd also check/replace the fuel filter.
     
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  11. I replaced the front coil when my 999 dropped onto one cylinder.
    Turned out to be the ecu coil driver, so it now has a 1098 type ecu in it, which are allegedly more reliable.
    Not saying it is that but it might be.
    Try the simple, cheap stuff first.
     
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  12. wot they all said, ^ could be many things but front coil notorious for causing problems particularly if bike damp/used in the wet recently.
     
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  13. Here are some more ‘free’ things to check.
    1. Fuel pump electrical connector under tank, check for chaffing on the wires
    2. Earth fly lead on ECU, check for breakages and Verdi Gris
    3. Right angle battery connectors, check for cracks/breaks
     
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  14. Wow, fantastic response everyone! I will go through the above suggestions and let you know the issue might take a few days though. Thanks for the welcoming.
    Steve
     
  15. If you are in auckland I can thoroughly recommend Ramon at moto magnet. He is very no nonsense.
     
  16. Hey all
    I managed to remove the coil the other day and noticed drops of water on the shaft (front cyclinder). I dried it, cleaned and dried the chamber where the spark plugs slips down and then removed the plug. It had a bit of rust and looked crap, i had the big service in April this year so thought this plug looked older than a new one would normally look after a few months?? I replaced with a new one, put the bike back together (I sprayed the rubber bits with a bit of soft sealant to help keep moister out)and its been sweet as...woop woop!! Again thank you all for the great advice.
     
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