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topping out with Lansdowne installed? (2012)

Discussion in 'Norton Commando Motorcycles (Classic)' started by nortonista, Jul 7, 2012.

  1. nortonista

    nortonista

    Joined:
    Mar 2, 2008
    Finally got a chance to put some time on my favorite backroads in West Marin County after a coupe super busy months. Just getting the hang of the front suspension after installing the Lansdowne kit .Got the compression about 2 turns out and the rebound about 1 turn out and noticing a fair amount of topping out on rebound even with minimum ripples in the pavement. The fork springs are standard and definitely not sacked as both from measuring them and from the average sag from fully extended to under normal load( 1.5 inches). What gives. Would like to know how the folks with the kit in their forks have them set up( turns out) . I like the compression damping better than before , but the topping out is annoying, Any feedback from forum folks would be greatly apprciated
     
  2. B+Bogus

    B+Bogus

    Joined:
    Jun 28, 2009
    I've had similar issues, but it's only been noticeable when moving the bike on and off the centrestand - I can't recall having any problems out on the road.
    I've started a number of rides with this in mind, but once out on a ride I forget about it. Could be an oil circulation thing?
    I've had the adjuster allen key in my pocket for fine tuning out on the road, but never used it yet.

    I believe the 'cure' for topping out is to fit extended top bushes, available from RGM in the UK or a separate sleeve solution from JS Motorsport across the Pond. They provide the hydraulic stop which the standard forks never did. I've just built a set of forks with the RGM bushes but they aren't fitted to a bike as yet, so can't report back on how they perform.
     
  3. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
    I know my Lansdowne dampers are the early type, but I have the rebound set to 1/4 turn out.
     
  4. john robert bould

    john robert bould

    Joined:
    Sep 26, 2009
    In responce from John Bould..
    I supplied Adrian Dedman from EKK racing a set of my dampers for a road going Commando. After fitting and testing he contacted me saying his forks knocked {topping out} badly.
    I thought now thats odd as John Dunn the Norton Owner club Tec adviser had just given the dampers a great review,which can be read on my web.
    So i suggested to Adrian mayby his forks where sticking giving a Top out effect,
    I suggested he sent me his forks for examination, The forks where worn in the slider bore, after 40 years it's not really surprising!
    I re-sleeved the sliders with steel inserts and fitted plastic bush's, and set them back.
    His email a few days latter was "John, the forks are now perfect! ,they are smooth and respond very well" He as ordered a second pair since.
    I have sent out 350 sets and a few [4] customers have contacted me with Knocking problens.
    My only Trade Customer is the HOLLAND NORTON WORKS who install them in customers bikes, Constant give the Dampers a full test in his own bike before offering them on their list of performance goodies. Constant as bought approx 10 sets and fitted them to his bikes.

    15 racing bikes now have the sets installed , many are repeat orders.
    Jack Ebb Manx racer swears by them ,and as both Manxs equiped
    Not forgetting Lansdowne winner luke Notton

    I have allways stated the kit will make good forks better and poor forks a lot worst!
    Binding or twisted forks will knock due to sticking bush'e being reluctant to respond smoothly to minor movements


    I tested these in racing bikes before offering them for road bikes. Duncan Fitcett did all the original shake down, it took 6 months before he give them the thumbs up.
    I have to admitt the first few sold did not have a cushion built in, but relied on some "twiddling" to stop the topping out ,as our forum moderater Lab will state shortly..i hope!
     
  5. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
    Yes, as you say, my Lansdowne dampers are the early version without the cushions, so I expect they probably need a little more rebound restriction than the latest model dampers but even so, I don't experience any topping out whilst riding.

    I should point out that I also fitted the RGM extended bushes at the same time I fitted the Lansdowne damper kit, and with the Lansdowne rebound damper backed off, the extended bushes proved to be completely ineffective when the forks were pumped, however that could be due to the 10w oil that John recommended for the Lansdowne kit and I may perhaps try 15w next time I change the fork oil.
     
  6. john robert bould

    john robert bould

    Joined:
    Sep 26, 2009
    This may interest user's.
    A few months ago Steward Tonge who is a great Engineer and racer, winning his class last year,
    Well he had a brand New manx in his work shop, the customer was having a set of lansdowne damper fitted.
    Stew phoned me saying the dampers where harsh, i suggested [dare i say it the forks in a brand new £30k bike where at fault!]
    But i did, turned out the bush's where to tight, and the front brake was to wide for the forks!
    Stew phoned me and said the front end was now 95% ,after some relieving and brake alteration...so even brand new bikes can have fork problems!

    Steward changed his Maxton dampers to the lansdowne's and refuse's to revert back..what more can i say?
     
  7. Dkt26

    Dkt26

    Joined:
    Jan 17, 2012
    Mine (4mths old) are absolutely awesome. They are the best upgrade available sling with a really great quality head steady.
    I now aim for pot holes.
    Love em
     
  8. john robert bould

    john robert bould

    Joined:
    Sep 26, 2009
    Cheer's ...
     
  9. Larry

    Larry

    Joined:
    Sep 8, 2007
    No problems with mine, best upgrade I made. Thanks John
    Larry
     
  10. mgrant

    mgrant

    Joined:
    Jul 19, 2003
    Same here. Outstanding upgrade. No topping out, knocking or clanking under any conditions.

    I did install the JS Motorsport turcite bushes when the dampeners were installed.

    Very satisfied with the results.
     
  11. nortonista

    nortonista

    Joined:
    Mar 2, 2008
    Thanks for all the replies. It was the forum members positive feedback on the damper assemblies that got me interested in the first place. I am enjoying the superior compression damping , particularly under hard braking, the only problem now being that the rear suspension( Hagon shocks) could use a bit more help controlling the back.As per the topping out I talked with Jim Schmidt of JS Motorsports and I plan to install both his Turcite bushings as well as the noise improvement bits when they arrive. Will report more on the subject after the next fork session. Cheers
     
  12. john robert bould

    john robert bould

    Joined:
    Sep 26, 2009
    Hi, What are noise improvement bits, :?: I am interested!
     
  13. B+Bogus

    B+Bogus

    Joined:
    Jun 28, 2009
    Ikons work well and match the damping quality of the front very well. I've also found the bike to be totally confidence inspiring when braking heavily - just when it's needed most!
     
  14. nortonista

    nortonista

    Joined:
    Mar 2, 2008
  15. jseng1

    jseng1

    Joined:
    Nov 26, 2009
    The top out prevention sleeves (that fit).

    [​IMG]

    The slippery turcite bushings that don't wear out your fork tubes.

    [​IMG]
     
  16. nortonista

    nortonista

    Joined:
    Mar 2, 2008
    Thanks for posting the pics ,Jim, Received the items and as soon as the alloy pin wrench type seal holders show up, I will install the bits and give it a try on the road. As I was able to ride with more gusto on the backroads with the Lansdowne kit installed, it may be getting closer to putting in your cam , pistons , rods and the flat slide carbs next. Cheers
     
  17. mgrant

    mgrant

    Joined:
    Jul 19, 2003
    I can't speak to the JS pistons and rods, but I do have Jim's stage 1 cam with the BSA style lifters installed. Great street cam with lots of pop throughout the entire range and pulls hard to the red line. IMO it also gives the bike a deeper, throatier sound. Probably just my imagination, but it sure does sound good. No issues with a hot rod idle or starting either.
     
  18. concours

    concours VIP MEMBER

    Joined:
    Dec 29, 2011
    Ancient thread, but, I’m ready to fit my (madass) Lansdownes, and I already have the extended bushes, to reduce topping. Is it ok to leave the extended bushes in place?
    Or, install standard length is preferred?
    57C649E3-014F-4275-A00B-97524993ED4B.jpeg
     
  19. acadian

    acadian VIP MEMBER

    Joined:
    Mar 5, 2010
    Extended bushes not necessary with Madass dampers, but they wont hurt anything if that's what you've got
     
  20. B+Bogus

    B+Bogus

    Joined:
    Jun 28, 2009
    A real blast from the past!

    I'd stay with the extended bushes. One worthwhile mod for smoother action is replacing the bottom steel bushes with something like Jim Schmidt's Turcite numbers.
    I had a set of Seeley forks rebuilt by Maxton recently and they use something similar for the bottom bush.
     

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