South Wales Trail Riders

    Front sprocket play

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    crm250dude

    Posts : 3472
    Join date : 2013-11-03
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    Re: Front sprocket play

    Post by crm250dude on Wed Oct 07, 2015 10:02 pm

    yes most definitely the symptoms of "death rattle"

    that description is spot on...

    "if you have the bike running in any gear under its own weight, ie down hill, you can hear the noise even worse."
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    mizzed

    Posts : 3084
    Join date : 2015-05-04
    Age : 38
    Location : Tafarnaubach

    Re: Front sprocket play

    Post by mizzed on Wed Oct 07, 2015 10:34 pm

    Update:

    stripped clutch and now at the primary gear, LH crank bolt was on tight, but impacted off with ease. with the nut off, woodruff key is there and intact but I can move the primary gear on the shaft and it moves around 1mm, impossible to measure, I will assume with a new woodruff key there should be 0 movement between the primary gear and shaft?




    curl666

    Posts : 544
    Join date : 2012-12-01

    Re: Front sprocket play

    Post by curl666 on Wed Oct 07, 2015 10:42 pm

    Yes the noise started off quite faint, then became more apparent with each ride.

    The primary nut will be loose on the clutch case side if your symptoms match. You can test if it's loose easily and I know a few people just re-torque it using the original nut and some locktite. But I replaced all components as described in the death rattle guide on Ktm forum. Which requires you to remove the clutch and basket.

    Well that was a waste of typing the above, I can see you've updated the post to say you've pulled it all off. Sleep

    I can't comment on the 0 free play at the woodruff key, I just replaced the parts refitted and the bike was silent. Sounded like a Wrf engine, lovely
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    mizzed

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    Location : Tafarnaubach

    Re: Front sprocket play

    Post by mizzed on Wed Oct 07, 2015 10:48 pm

    Hmmnn, it wasnt finger loose,

    but i dont think there was anyway it was pulling this torque:

    Hexagon nut, primary gear M20x1,5 Loctite 243 + 150 Nm

    I would have expected a few clicks with the impact, but it flew off.
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    mizzed

    Posts : 3084
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    Age : 38
    Location : Tafarnaubach

    Re: Front sprocket play

    Post by mizzed on Wed Oct 07, 2015 11:25 pm

    Got the lot stripped down,


    woodruff key does has wear:-
    [You must be registered and logged in to see this image.]

    Not a huge amount in the grand scheme of things but a definite grove has been cut out enough to let it move on the shaft, i will assume this will only occur if its not torqued up to spec.

    Was your similar?

    curl666

    Posts : 544
    Join date : 2012-12-01

    Re: Front sprocket play

    Post by curl666 on Wed Oct 07, 2015 11:48 pm

    Yes mine was worn similar to the above.

    My primary nut was finger tight, probably just caught it in time to avoid an engine rebuild.
    But my friends 450 was similar to how you describe, tight but not to spec.
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    mizzed

    Posts : 3084
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    Re: Front sprocket play

    Post by mizzed on Thu Oct 08, 2015 12:00 am

    Sound, thanks again for all the info curl, been a massive help, will let you know the outcome
    Cheers mate!
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    mufynman

    Posts : 3144
    Join date : 2012-10-08
    Age : 49
    Location : Wye Valley

    Re: Front sprocket play

    Post by mufynman on Thu Oct 08, 2015 7:39 am

    whats a torque wrench ?
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    wolfy

    Posts : 6811
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    Age : 49
    Location : Care Home, but sometimes they let me out

    Re: Front sprocket play

    Post by wolfy on Thu Oct 08, 2015 7:56 am

    crm250dude wrote:yes most definitely the symptoms of "death rattle"

    that description is spot on...

    "if you have the bike running in any gear under its own weight, ie down hill, you can hear the noise even worse."

    Its not as simple as chain slap is it ? one or two stiff links will make it worse.
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    mizzed

    Posts : 3084
    Join date : 2015-05-04
    Age : 38
    Location : Tafarnaubach

    Re: Front sprocket play

    Post by mizzed on Sun Oct 11, 2015 9:58 am

    Im still not convinced this countershaft movement is normal.

    Could anyone with and rfs engine check if they have shaft movement like this please?


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