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Thread: Right you clever lot ???

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  1. Right you clever lot ??? 
    #1
    Diamond Member DC's Avatar
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    After yesterday's long Idle period when it wouldn't start and what I assumed was nothing more than letting it cool down for ten to fifteen minutes and all was fine , I went out for a localish ride this afternoon to Marlborough and the bike cut out out near Ogbourne ! I wasn't sitting around with the engine running , just riding with plenty of air to keep it cool . I sat again for ten minutes and she started fine and ran all the way back to Swindon until about half a mile from home and did it again , another breather and off we went again . This has never happened before in 8 years . I know there's not a lot of information here , but it was never an issue until it sat there for a prolonged period yesterday . Is it possible I've finished the spark plugs off ???
     
     

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    #2
    Platinum Member WR6133's Avatar
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    Coils craping out when they heat up? Only way to test that theory though would be with known good ones.
     
     

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    #3
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    for the un initiated... BIKE?
    my guess , if the plugs have been changed could be a coil pack going down, sounds like a heat problem rather than fuel evaporation.
    always the possibility of plug leads going down
     
     

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    #4
    Diamond Member DC's Avatar
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    Quote Originally Posted by WR6133 View Post
    Coils craping out when they heat up? Only way to test that theory though would be with known good ones.
    You might be on to something there WR , nice one !!! Since reading your post , have done a bit of digging on youtube and found a guy who describes the symptoms pretty much exactly .

    Is it possible that the ignition coils , having been in there for 8 years may have deteriorated further due to letting the bike sit idling for a prolonged period , thus overheating ?

    https://www.youtube.com/watch?v=W0HtFSyz6bk
    Last edited by DC; 14-03-16 at 10:02 PM.
     
     

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    #5
    Diamond Member DC's Avatar
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    Quote Originally Posted by wheelers View Post
    for the un initiated... BIKE?
    my guess , if the plugs have been changed could be a coil pack going down, sounds like a heat problem rather than fuel evaporation.
    always the possibility of plug leads going down

    Sorry Wheelers , it's a 2008 Triumph Bonneville 865 EFI .
     
     

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    #6
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    ah , Triumph..
    one of my customers has a Trophy 900, tell tale sign was missing and no rev counter. had a terminal broken in the coil pulls out and pushes in, changed and its ok.
    another had a speed triple, coils over heated so he ran washing machine pipe (any pipe really eg hose) from the head stock (out of sight) onto the top of the coils. cooled them down so no further problem.
     
     

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    #7
    Active Member tomearp's Avatar
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    the described behaviour can be characteristic of an overheating coil. basics checks of the resistance of the coil's windings (as per the video) are a good start and will quickly identify a dead one. intermittent issues are of course harder to track down.

    it is worth also checking the other parts on the secondary side of the coil, so any HT leads etc. (i'm not familiar with the ignition system on the bonneville) and the condition of the spark plugs. a heavily fouled/intermittently firing plug, or a high-resistance connection somewhere can create an over-voltage condition in the coil which, over time, could damage the insulation of the windings. it could be that in your case the insulation was deteriorating due to that (or age) and a period of idling caused an excessive build up of heat that has finally caused something to fail.

    say, for example, it has caused a crack in the insulation of the secondary winding. it may well be that when cold the crack is closed or so narrow that resistance measurements look fine, and the engine can operate normally.
    in operation the coil will heat up and the winding wire will expand, causing the crack to start to open. if you start to get arcing at this point in the circuit then clearly that is lost power that never reaches the spark plug, so you get a weaker spark.
    a weaker spark does not necessarily mean the engine will immediately stop. when cruising at moderate revs the conditions within the combustion chamber are (crudely, without getting into details) more conducive to the creation of a spark, so a reduced voltage at the plug will still create a good enough spark for combustion. in this scenario the problem would most likely manifest when you idle or run at low revs.

    as WR suggests it's difficult to test without having some known good coils, in which case you've likely already spent some money :S
     
     

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    #8
    Diamond Member Toph's Avatar
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    Now this thread is exactly what makes this forum great... top advice from peeps who have the knowledge..fault finding can be a nightmare.
    Hope this sorts your problem Andy.
    and Andy...your recent mods on the Bonnie look superb, well impressed mate.
    Last edited by Toph; 15-03-16 at 07:58 PM.
    There's no feelin' like 2 wheelin'
     
     

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    #9
    Diamond Member DC's Avatar
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    Quote Originally Posted by WR6133 View Post
    Coils craping out when they heat up? Only way to test that theory though would be with known good ones.
    Well spotted that man !!! Hit the nail well and truly on the head !!! Nice one WR . Can you tell I'm in a good mood ? I hunted out the resistance values for that particular unit and how to test for duff coils , Also tested the HT resistance and they were as they should be . The primary coils were spot on but the secondary coils were reading as an open circuit with no reading at all . I think as Tomearp suggested , sitting with the engine running , the excessive heat has finished them off . Will order Up a new unit tomorrow.




     
     

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    #10
    Diamond Member DC's Avatar
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    Quote Originally Posted by Toph View Post
    Now this thread is exactly what makes this forum great... top advice from peeps who have the knowledge..fault finding can be a nightmare.
    Hope this sorts your problem Andy.
    and Andy...your recent mods on the Bonnie look superb, well impressed mate.
    Well said Toph ! , I didn't have a clue this time yesterday and with a bit of knowledge and a nod in the right direction from peeps on here ,I had a crack at something I had no prior knowledge of . It's been a fairly steep learning curve today , but well worth it , Thanks Chaps !!!
     
     

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