Movement in steering headstock

Discussion in 'Maintenance' started by Lucky13, Apr 10, 2019.

  1. Lucky13

    Lucky13 Member

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    Hey guys

    Recent MOT highlighted there is movement in the headstock, the bikes only got 10k miles ( driven very gently with zero track days ) so I’m hoping this just needs tightening.

    Can anyone give me a quick idea of what I need to remove to tighten this up, or a recomended tool that can sneak in the head stem area ( if there is space to tighten this )

    Loads of experience in working on bikes so if I need to pull off a lot of parts fine but I was hoping to avoid this just to tighten a nut.

    CBR1000RR 2008

    Thanks
     
  2. Lucky13

    Lucky13 Member

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    Anyone ?
     
  3. nigelrb

    nigelrb Senior Member

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    No reply probably because no one's done front end work other than change over forks.

    In the absence of other replies, and from my experience on much older bikes, the head stem will usually be tightened via a 'C' spanner nut beneath the top yoke. (I assume you already know this) . On looking at my 2011 (same front end as 2008) it seems there's little difficulty in removing top yoke, provided you can create enough slack in the ignition switch wiring.

    Given that you've got loads of experience in working on bikes, once you've removed the yoke you'll see exactly what you're faced with.:)
     
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  4. BoroRich

    BoroRich Elite Member

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    Just going to chuck this into the mix. I don't suppose the bike has the big piston forks fitted retrospectively, does it?
     
  5. auag

    auag Active Member

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    I've just done the head bearings on one of my 07s.
    They'll be small differences to an 08 but these are worth saying;
    Be very cautious resetting a head bearing that's been riden while loose. I would definitely not try to nip it up. Strip the front off and look closely for signs of marking or brinnelling on the races. Mine uses deep groove ball bearings, yours may have taper rollers but either way if the rolling elements have flatted the wear will accelerate and the bearing can literally jam. I know of a guy who nipped up a head bearing and ended up with a cage on his leg.
    If the races (all 4no) are still good then they can be repacked with an EP2 grease, otherwise you'll need to replace the lot.
    Assuming it's serviceable you'll need a castellated socket and a 45mm Cspanner. I bought mine from eBay where someone was selling copies of the Honda workshop tool, about £20.
    The Honda copy socket is critical because you must preload the bearing set, mine is 20Nm, yours may be different but will be in that ballpark. Head bearings must be preloaded.
    It's a straight forward job but a lot easier to do right if you've a workshop manual. The locknut above the upper clamp is about 130Nm.
     
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  6. Lucky13

    Lucky13 Member

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    Thanks that’s really helpful, as my MOT is next week so I was going to get this issue sorted beforehand l... I’ve bought the Honda Socket so I can preload as you advised

    By the way can you remember what you had to remove to get to the head bearings ?
     
  7. auag

    auag Active Member

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    Pretty much everything on the SC57/A is more awkward than the later bikes, they seemed to have forgotten to package for maintenance, so this should be more simple for you.
    Forks out
    Top shelter off
    Steering damper off
    Upper bridge off
    Bend back tabs, remove lock ring
    Remove upper castellated ring
    Lower clamp and bearings fall away
    Check races and rotating elements super closely
    If good, reverse of above but;
    Preload bearing set
    Fit tab ring and lock ring
    Ensure castellated ring stays still
    Tighten lock ring till tabs align
    Bend tabs, check free movement
    Fit upper bridge
    Fit forks to align bridges
    Tighten top lock nut, 100+ Nm
    Reassemble damper etc

    Honda do also recommend a small weigh scale is used afterwards to double check the drag caused by the preload. Personally, so long as you are sure you've set the preload and can feel the bearings are slightly tight but smooth I think that's good enough.
    If you need to replace the frame and steering tube races then you'll need more special tools, or make copies of Honda's designs.
    If it comes to that remember warming the head tube will make removal and insertion of the cup races much easier.
    A hot air gun will raise the frame locally by 50degC easy and that will remove most of the interference fit.
     
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  8. hitch

    hitch Well-Known Member

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    What does "Preload the bearing set" mean and how does one achieve it?
     
  9. auag

    auag Active Member

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    Preloading a bearing means to slightly tighten beyond touching to leave a positive compression of the rolling elements into the races.
    Not all bearings are preloaded, it depends on the duty.
    A relatively lightly loaded but high speed duty like a wheel bearing can be sealed with a tiny clearance to accommodate expansion as the bearing warms up.
    A motorbike head bearing is an example of the opposite situation. The bearings hardly rotate/move at all but are under very high loads and spikes such as hitting a pothole under heavy braking. Here the bearing is prone to slide or skate rather than roll and this will quickly create a flat on the rolling elements, be them balls or rollers. To discourage this and to oblige the elements to roll on the races and not slide, a small positive pressure is left on assembly, called a preload.
    Once a flat has occurred the temptation is to nip up the slack and so the situation becomes very dangerous, and can jam the lot solid or at least cause notchy steering.
    Preload is achieved by after closing the set till hand tight, to then apply a further torque in addition.
    It's not a lot, on my RR7 it was only 20Nm.
     
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  10. auag

    auag Active Member

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    As I mentioned the Honda manual does say you should check the preload with a small weigh scale.
    I ordered a 0-5kg Salter, handy to have anyway.
    The actual preload I used was 27Nm (not 20 as I said earlier) and Honda say the drag measured by the scales should be 1.3-1.9kg
    Mine checked at 1.5kg, so worth doing I feel.
     
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