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Backfire

Discussion in 'Bling and Appearance' at netrider.net.au started by RobE, Jan 4, 2008.

  1. I think it is a backfire, even it is more of a burp than a bang.



    My 1995 CB 250 has travelled 75,000 but only recently with me on it.

    Just every so often a quick release of the throttle will bring one on.

    Is this normal or is it a symptom of something that needs to be followed up?
     
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  2. My CBR900 has a slight popping when I get off the throttle quickly, probably a Honda thing :)
     
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  3. My Beemer did it too!

    Apparently it is just burning a bit of extra fuel.

    Enjoy the sounds and don't worry is what I do!

    WGM
     
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  4. A backfire on deccel means it's running a bit lean on idle mixture.

    A backfire on accel means it's running a bit rich on idle mixture.

    Adjust the idle mixture screw 1/4 turn accordingly.
     
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  5. My bike in the recent month has been giving off a bang 1 in 5 times i start it. Scared the bejessus out of me the first time it happened.

    Get the normal burps when going downhill in gear.

    Serviced 1000 km ago.
     
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  6. Is it a carb backfire? Or is it exhaust?

    You should be able to tell by listening carefully. I'd get it checked - neither should happen.

    Cheers

    Trevor G
     
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  7. Anyone know anything about VTR250's backfiring on start up? Every now and then (prob same as above poster - one out of every five) it'll backfire and shoot flame...always when starting it up in the morning.

    Also, I was actually leaning it through a roundabout the other day and as it was tipped over (gotta love the roundabouts on the Sth Gippy ;) ) it made a loud pop/backfire sound. Anyone know what could have caused that?
     
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  8. And you want to stop this? MADNESS! :grin:
     
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  9. *gets a little misty-eyed as he remembers back to Formula SAE, where he and his teammates deliberately left the high-rpm closed-throttle map very rich with a (relatively) retarded ignition map, so that the CBR600F4i motor in the car would belch wicked flames on gear-changes and overrun* :LOL:
     
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  10. Possibilities are:

    1) Bad spark plug or plugs

    2) Bad ignition coil or ignition trigger unit (unlikely...but possible)

    3) Incorrect ignition timing ( unlikely but still possible).

    When were the plugs last changed?

    Even if the answer is "recently," I have had new plugs which have failed...it's a cheap first try.

    All the best

    Trevor G
     
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  11. +1.

    Over the years, I must have had half a dozen NGKs that were dead straight from the box.
     
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  12. Take it to a mechanic

    Take it to mechanic, to many variables.
    To rich, to lean, is it carbs, is it exhaust coking?
    Does it have after market exhaust?
    What air filter does it have?
    What plugs are you running?

    See your friendly neighbourhood mechanic and get it diagnosed
     
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