Paging Sweller - Le Mans

Discussion in 'Classic Motorbikes' started by 'Hog, Aug 15, 2005.

  1. 'Hog

    Guest Guest

    Hmm... the R80 does that in a band at 75+ MPH (in 'test' conditions,
    obviously). It's likewise set up for dual disks.

    I wonder...


    Guest, Aug 17, 2005
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  2. 'Hog

    Champ Guest

    That sounds about right. I recall that it was nothing to do with
    efficacy of the brakes themselves, but to do with handling/steering.
    Champ, Aug 17, 2005
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  3. 'Hog

    platypus Guest

    Airhead boxers are notorious for that - the steering damper on older ones
    wasn't just for sidecar use. This was the case with drum-brakes models, and
    early disc versions, which had ATE calipers behind the forks. The newer
    ones carry their Brembos in front of the forks, and will flutter just like
    the older ones.

    There's a long straight hill going into Thornbury, where you can take your
    hands off and a bike will maintain about 40-50 mph. On any of the BMWs I've
    had since I moved here, the bars will flutter through about 30deg until I
    choose to stop them. By contrast, my old Silverwing was perfectly steady: I
    could stand up and stretch, and sit down again, without the slightest
    uncommanded movement from the bars. It had, it must be said, a single
    caliper behind the fork leg.
    platypus, Aug 17, 2005
  4. 'Hog

    Guest Guest

    Do you mean the one on the northern road, SP to the industrial estate
    off the A38? If so I know what you mean exactly!
    And probably more engine mass!! I've two friends who've had them, one
    with a Watsonian fitted. I still think they're an acquired taste. The
    solo m/c was fine for a while then *everything* went wrong, very
    expensively. The sidecar one was cool though - beautifully-matched
    maroon paint job, although I can't really appreciate the finer points of
    sidecar handling!

    I've got to replace the hoses and the rubber gaitery-boot things on the
    fairing before the MOT (I know the boots don't matter, but they look
    dreadful. This obviously involves dropping the forks out, so I'll have a
    look at a swap-over then.

    It'll be really nice if it's do-able and works, because it's worse when
    the front is lightly loaded, and I much prefer using panniers to a tank
    bag, so it's a PITA when touring.

    <thinks> I might give James Sherlock a ring first. They'll be doing the
    MOT, probably, and if anyone knows of gotchas doing this, they will.


    Guest, Aug 17, 2005
  5. 'Hog

    platypus Guest

    Yep, Grovesend/A38 down to the roundabout on Morton Way. Fine view of the
    Severn and the crocked nuke.

    I saw an outfit like you describe outside the long-vanished bike shop on
    Cotham Hill, about seven or eight years ago.
    One thing to do, if you're taking the old gaiters off, is - before you
    remove the forks themselves - cut the gaiters away, and put a bit of plate
    glass across the stanchions. If it rocks, your forks are twisted, and
    you'll need to sort this out first.
    I think you've got more than the usual problem there. My steering only
    flutters when I provoke it, otherwise it's fine. This includes hauling wife
    and loaded panniers across Europe.
    Is that not a bit far to go for an MOT?
    platypus, Aug 17, 2005
  6. 'Hog

    'Hog Guest

    Well it didn't sell, no surprise. The final bid price is what it's
    worth, wonder what the reserve was.
    For a rat I don't think it really matters what the tank looks
    just need to be painted black!
    Single tube spine frame I guess so easy to find an alternative tank

    'Hog, Aug 17, 2005
  7. 'Hog

    Guest Guest

    Know it well.
    Loads nicer than the pretend-tourer version. I can see that being a bit
    more fun, but I can understand your reluctance re- knee-down corners!
    Sounds like Roger's but I don't think he owned it back then. He got it
    off an old geezer who might well have patronized 'Bristol 6".
    Good point.
    Maybe. I've been putting off looking at it for a while. I need to work
    through the lot - swingarm bearings, fork fluid/springs, head play, etc.

    It may just be that I notice it more, or even that I need to tweak the
    Koni more carefully (prefer a harder ride, generally, but I can see that
    wouldn't exactly damp the oscillations).

    It needs some experimentation probably, before leaping in. It's most
    probably rider incompetence, as you don't hear of loads of people
    swapping the brakes round to fix it.

    Incidentally, do you rate those milled triple-clamps that occasionally
    turn up on eBay? The top plate does look flimsy, but then it's not doing
    as much as the lower one.
    Yes, but it's a nice trip, I get to play with something different for
    the afternoon, and I get them to service/balance the carbs, etc. at the
    same time. It's been off the road for awhile, and the trip down is a
    good chance for a legal shakedown before the MOT. If anything's
    seriously bogged, they've almost always got the right part in-stock,
    which saves lots of grief.

    Mind you, I got totally soaked last time on the way there - slow traffic
    and thunderstorms near Taunton :( It's great for 'dryness' at sensible
    motorway speeds.


    Guest, Aug 17, 2005
  8. 'Hog

    platypus Guest

    I reckon you need to go through all the standard remedies before you start
    playing around with the brakes. If it's enough of a problem that you're
    unable to use the panniers, then that's a lot worse than standard. If
    you're down at Sherlock's, talk it over with them.
    Hog does. I probably wouldn't notice the difference.
    platypus, Aug 17, 2005
  9. 'Hog

    Guest Guest

    It's not *that* bad. I took it heavily-laden up to Scotland about 18
    months ago, and it was a nuisance on the M6. Also on regular runs down
    the M5 if I push it, but that's usually almost unladen.
    Yup. Good advice.

    Guest, Aug 17, 2005
  10. 'Hog

    'Hog Guest

    If you mean Ultimate Source type top yokes then too bloody right, makes
    a world of difference twinned with some Progressive Suspension or Hagon
    progressively wound fork springs. I have this with some EBC HH pads and
    goodridge hoses. One takes the most amazing liberties on bumpy roads.

    'Hog, Aug 17, 2005
  11. 'Hog

    Guest Guest

    I've a set of Goodridge hoses waiting to go on right now. Will take
    another look at the 'Ultimate Source' stuff...

    Thanks for the info.


    Guest, Aug 17, 2005
  12. 'Hog

    Ovenpaa Guest

    Sometime around Wed, 17 Aug 2005 08:38:59 +0000, platypus babbled on

    I have an '86 r80 with twin disks, it is quite stable all things
    considered (1) and seems to hold a reasonable line even at highish speed.
    In fact it seems better than the Uberbeast when pushed to 3 figures.

    (1) 150k on the clock being one of them.
    Ovenpaa, Aug 17, 2005
  13. My R60/6 seems pretty well behaved, albeit at the moment it's not pulling
    more'n 85 on the flat, I think over the winter some attention to the engine
    will be in order. It's crudding up the starborad plug, and smoking a bit,
    and rattling a bit - I suspect valve guides. Whether it's worth faffing
    about trying to do them/get them done, or whether it'd be better to exchange
    the heads, I dunno.

    It had a set of rings not that long ago, so they may be OK.
    Austin Shackles, Aug 17, 2005
  14. 'Hog

    Ovenpaa Guest

    Sometime around Wed, 17 Aug 2005 21:29:41 +0100, Austin Shackles babbled
    Timing chain is a little noisy and the front disks are shiny otherewise it
    is a good un.
    Ovenpaa, Aug 17, 2005
  15. 'Hog

    Lozzo Guest

    Ovenpaa says...
    Oxymoron alert.
    Lozzo, Aug 17, 2005
  16. 'Hog

    Ovenpaa Guest

    Sometime around Wed, 17 Aug 2005 23:22:11 +0100, Lozzo babbled on about:
    Dont you call me that!
    Ovenpaa, Aug 18, 2005
  17. 'Hog

    TOG Guest

    You're nearly there. It's because having the calipers forward of the
    fork legs puts the weight and forward (well, duhhh) and thus you've got
    a lot of inertial load forward of the fork, which can promote steering

    I think.
    TOG, Aug 19, 2005
  18. 'Hog

    platypus Guest

    The axis around which the forks rotate is a line through the headstock.
    This runs down the back of the forks. The further a component is from this
    line, the more effort it takes to rotate the forks, and to stop them
    rotating. Putting the calipers behind the forks makes the turning effort
    less, and the rotation of the steering assembly quicker and lighter.
    platypus, Aug 19, 2005
  19. 'Hog

    Pip Luscher Guest

    You're nearly there. It's because having the calipers forward of the
    fork legs puts the weight and forward (well, duhhh) and thus you've got
    a lot of inertial load forward of the fork, which can promote steering

    Umm, that's pretty much what I said. So ner ner nee nerr nerr!
    Pip Luscher, Aug 19, 2005
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