Spragged off!!!

Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by ACP, Nov 28, 2012.

  1. ACP

    ACP Adventurer

    Joined:
    Aug 15, 2008
    Oddometer:
    84
    Location:
    New Forest NP, Hampshire
    Anyone know anything about the starter freewheel (sprag)?

    My 04 950S (only 17k miles) has been having trouble starting when hot. All the symptoms and noises, going by the experience and threads of others here seem to point to the starter freewheel (sprag clutch) being the culprit.

    BUT, I've taken the thing apart, and all the components look in good nick and as I think they should, not all mangled with major scraping between components and flat spots etc. as seen on TB0554 and here

    So, what I want really is confirmation that these components are indeed shagged before I go and spend £450 on a new assembly which includes an ignition rotor I don't need! Can anyone confirm for me that these components are OK or not?

    Here are the:
    freewheel hub
    [​IMG]

    sprag clutch
    [​IMG]

    starter freewheel
    [​IMG]

    It's definitely NOT a clacking torque limiter prob as it doesn't have one! The only other suspects I can think of are the starter solenoid which I've checked for corrosion / poor contacts and is fine. The bike has a new and well charged battery. Is there any chance that the starter motor itself may be at fault and not spinning up fast enough to engage the sprag?

    T.I.A.
    Andy :D
    #1
  2. gefr

    gefr Life is a trip

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    The little beans looked flat one one side. The problem appeared as hissing sound and the motor would not start, draining the battery.
    In case you move on to replacing the sprag, you can buy the sprag for the 640 and use the little beans, replacing the old ones.
    However very unlikely on your almost new bike.
    Maybe you need to check if your freewheel is spinning on the cranckshaft. You probably do not have a woodruf key installed as later models. Could this be your problem?
    Cheers.
    #2
  3. ACP

    ACP Adventurer

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    Thanks, I'm aware of the 640 bean swap replacement. I think I must have read your posts on it. The ones in the sprag now don't appear that worn. Do you think it'll help in this case?

    It's defo not the flywheel spinning on the crank. It is indeed keyed thank feck :wink:
    #3
  4. gefr

    gefr Life is a trip

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    That would be the first step.
    #4
  5. rossguzzi

    rossguzzi 990 Adv.

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    I could be wrong, but on Aprilias (they are similar) there is a long thin spring that goes around the outside. If stretched it causes problems. Some have shortened it and cured certain problems.
    #5
  6. TcRulz

    TcRulz Been here awhile

    Joined:
    Dec 25, 2010
    Oddometer:
    289
    Location:
    Home of all things fridgid - Bathurst.
    I'm with Gefr:clap. My 03 950A doesn't have a woodruff key that stops the rotor from spinning on the crank. Seeing as how the freewheel locks the starter to the rotor, my guess is the rotor is spinning on the crank. Needs to be really tight as it's only a tapered fit.

    Just replaced my freewheel at 73000km only because it was apart:eek1....in comparison yours is new:D.
    #6
  7. MortimerSickle

    MortimerSickle Semi-Adventurer

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    Rainville, Orygun, where moss is a road hazard.
    If you have an un-keyed flywheel, and are interested in used parts, send me a PM.
    #7
  8. ACP

    ACP Adventurer

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    the spring looks in excellent condition all the way around.

    It DOES have a Woodruff key so it's not the flywheel spinning on the crank. Thanks for the offer
    #8
  9. uraberg

    uraberg whosaberg?

    Joined:
    Apr 21, 2009
    Oddometer:
    707
    Location:
    Buffalo, NY
    In my experience, difficulty turning over the engine when hot indicates a worn starter motor.
    #9
  10. charlie264

    charlie264 Long timer

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    The sprag bearing should grip instantly in its non rotational direction; even if the starter motor is lazy it should transfer the torque of engine to motor. Check the sprag bearing by hand holding it in a vice, I’ve not taken the starter system out of the LC8 but if the starter motor is still turning and the sprag is good, only two possibilities, gear is slipping on the starter motor shaft or its spinning in the wrong direction.

    If you need a new sprag bearing try AR bearings first http://www.arbearings.co.uk
    #10
  11. ACP

    ACP Adventurer

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    Cheers Charlie,

    I'm going to put it back together and see what happens. If it keeps doing it I may try replacing the sprag bearings followed by new parts (last resort)....

    Just need to wait for the Loctite 648 to turn up!
    #11
  12. MortimerSickle

    MortimerSickle Semi-Adventurer

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    If you can't find 648, Permatex High Temperature Sleeve Retainer should do the trick. IIRC, it specs out even stronger than 648.
    #12