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Suspension adjustment

Discussion in 'Norton Motorcycles (Modern)' started by BikerBore, Jun 29, 2019.

  1. BikerBore

    BikerBore

    Joined:
    Oct 8, 2018
    I'm about 15st 5lbs.

    If you want to trying my settings they're:

    Front Compression (Bottom) - 18 clicks out from closed
    Front Rebound (Top) - 22 clicks out from closed

    Rear Compression (Top) - 3 clicks out from closed
    Rear Rebound (Bottom) - 22 clicks out from closed

    Given how hard the rear springs are I'd recommended removing all the preload (no rings showing).

    Front preload I cannot remember at there was quite a bit off adding a turn or three then taking it away until got sag right. I'd say you'd want to set your own sag anyway.
     
    contours likes this.
  2. contours

    contours VIP MEMBER

    Joined:
    Jan 1, 2012
    And you found the stock settings too hard or too soft?
     
  3. BikerBore

    BikerBore

    Joined:
    Oct 8, 2018
    Too hard.
     
  4. contours

    contours VIP MEMBER

    Joined:
    Jan 1, 2012
    Oh - that is a good reference then. I am around 170 LBs and find the suspension a bit bouncy. Makes sense now.
     
  5. Britfan60

    Britfan60

    Joined:
    Jan 5, 2014
    Great thread. Finally learned a stone pound conversion.
     
    contours likes this.
  6. Bluey72e

    Bluey72e VIP MEMBER

    Joined:
    May 8, 2019
    Mean while......!! back in the civilized world we use Kilograms as defined by International Bureau of Weights.

    :p
     
    contours likes this.
  7. BikerBore

    BikerBore

    Joined:
    Oct 8, 2018
    It's a British bike so I used a British weight scale :p

    Missing the days when we had 240 pennies to the pound (£) :D
     
    contours likes this.
  8. Bluey72e

    Bluey72e VIP MEMBER

    Joined:
    May 8, 2019
    I haven't found any Imperial bolts on the 961 yet (about to get spammed by the nerds pointing them all out)

    :p
     
  9. jan nelder

    jan nelder

    Joined:
    Feb 18, 2018
    how about starting a new thread, like 6000 miles one, where those who have found a good set of settings can list them along with their weight. Need to have headings for click direction etc!
     
  10. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    Now that’s a great idea, maybe Richard or Matt could start marketing whitworth replacement kits for 961s...!
     
    Bluey72e likes this.
  11. lcrken

    lcrken VIP MEMBER

    Joined:
    Mar 15, 2009
    I've been riding a bit now with the softer rear springs, and I'm really happy with them. The rear no longer bounces me out of the seat on bumps, and I can now get the sag in the right range with reasonable pre-load adjustment. Rear pre-load is now at 2 rings showing, compression is 4 clicks out (limit of adjustment), and rebound is 20 clicks out. Front forks are on minimum pre-load setting, 16 clicks out on compression, and 18 on rebound. I'm still experimenting, but these settings are working pretty good. As I mentioned earlier, these are the conventional forks, no luggage, and I weigh 185 lbs.

    I suspect the front could stand a slightly softer spring, but I'm not sure it's worth the effort. I have to keep reminding myself that this isn't a race bike, so I need a setup that works on the street, not the race track.

    Ken
     
  12. lcrken

    lcrken VIP MEMBER

    Joined:
    Mar 15, 2009
    I've been riding a bit now with the softer rear springs, and I'm really happy with them. The rear no longer bounces me out of the seat on bumps, and I can now get the sag in the right range with reasonable pre-load adjustment. Rear pre-load is now at 2 rings showing, compression is 4 clicks out (minimum limit), and rebound is 20 clicks out. The front is on minimum pre-load, with 16 clicks out on compression and 18 on rebound. I'm still experimenting, but these settings are working pretty well.

    I suspect a slightly softer front spring would be better, but not sure it's worth the effort. I have to keep reminding myself that this isn't a race bike, and it should be set up for "brisk" street riding, not the race track. Race tracks are generally much smoother than some of the bumpier roads I ride.

    This is for a 2014 Sport with conventional forks, no luggage, and I weigh 165 lbs.

    Ken
     
  13. Welshrugby

    Welshrugby

    Joined:
    Jan 18, 2018
  14. lcrken

    lcrken VIP MEMBER

    Joined:
    Mar 15, 2009
    Good discussion. The information in the factory service manual is also pretty detailed. I'd suggest starting with the values in the service manual. I've found it easier to start working with the front forks first, and once they are sorted to move on to the rear. I'd also suggest when making compression and rebound changes in the forks, make a significant change, like 4 or 5 clicks to see what effect it has. That should tell you which direction to go. Then you can refine it in smaller increments. It's pretty hard to tell any difference in a one click change. It also seems simpler to me to work with the front compression adjustment first. I reduce it in stages until it gets close to bottoming on extreme braking, and then add just a little back in to have some margin. You can then work on the rebound setting. I keep backing it out until the front end starts to feel a little unstable under hard cornering. On a race bike, that might be where you want it, but on a street bike I crank in just enough rebound to make it feel solid in the corners. At the rear, I also work on compression first, mostly putting in enough that the bike doesn't squat too much under hard acceleration, but not so much that it kicks me off the seat in the bumps. The Ohlins rear shocks only offer 4 clicks of total adjustment, so it's pretty easy to find the best setting. With the stock stiff springs, unless you're carrying a heavy load, you'll probably end up with 4 clicks out, the minimum amount of compression damping you can get. With a passenger and/or luggage, you might need more. To sort the rear rebound setting, I have a bumpy road I use for testing, and I mostly just play with settings until the bike feels like it is tracking the bumps as best it can. With too much rebound damping, the rear will pump down over a series of bumps, and feel really harsh. Might even feel it loosing traction as it bounces off the bumps. With too little rebound, the rear end feels like a pogo stick.

    Optimizing suspension settings is really an iterative process. You start by getting the sag settings somewhere in the acceptable range, then work on damping adjustments. But you might later find yourself changing the preload settings for one reason or another (heavier loads, more or less squat or dive, or softer in the bumpy stuff, or more stable at high speed on smooth tracks, or?), and then you might have to revisit the damping settings to suit. There really isn't any "one size fits all" setting. Getting the fine adjustments right depends a lot on both how and where you ride. The right settings for a track day addict aren't likely to be the best for touring in the twisty mountain roads or freeway flying with a passenger. In the end, it comes down to what works for you.

    Fortunately, on a street bike, you can play with the settings to your heart's content with no risk to life and limb unless you really push the limits. It gets a little more critical on a race track.

    Lots of good reference books out now on sport bike and race bike suspension tuning, for anyone who is really interested. And they mostly agree on the basic principles of suspension tuning.

    At least we don't have to worry about having both high speed and low speed damping settings to adjust, like the high end race (and some street) bikes have. I'm not sure I'd ever get that all sorted out. Actually, I'm not sure I really have it sorted out with what I have now. But it's kind of fun trying, and unlike engine mods, it doesn't cost anything.

    Ken
     

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