Yss shocks

Discussion in 'Technical' started by David Race, May 4, 2011.

  1. Indeed wise comments.
    I too once had a good YSS set up on my Africa Twin for awhile.
     
    • Like Like x 1
  2. Pensionist,
    Opinion was not meant to offend, just an opinion to OP and any of our fellow members....
    If you are experiencing nirvana with YSS: more power to you!

    Cheers.;)
     
  3. In 2014 I bought some twin YSS piggyback shocks for my GT1000, direct from the YSS factory in Thailand, and they shipped to Cambodia.
    It wasn't easy setting up the initial communication due to the language barrier
    For technical info, they eventually referred me to their R&D Director, Mr Harrie Essens.

    The quality is ok, 24,000 miles trouble free so far.
    They use progressive springs, as per OEM, but I would prefer a linear rate spring which they don't stock.
     
  4. Bill,

    I'm guessing thats the GT1000 Ducatti? Regarless, progressive springs ( not to be confussed with Dual Rate Springs) are very difficult to tame (Calculate correct sag and squat) to any machine in a single mono shock application..... Dual Shocks with a Progressive Spring are problematic at best.... Unless you know the Spring Rates and have tried someone elses machine with them on and the Pre-load was just for you......... Yeah, I know, in a perfect world!

    We shy away from progressive unless (as in your case) we have exhausted our search for manufacturers that offer the other tyes of springs. Progressive applications would typically be for a rider or riders who are doing extreme off road riding or abusing the Max Load Rating of the street machine they own. A Progressive Spring is the hardest to calculate the Static, Ride Sag and Bikes Squat.

    For Example, If I have a rider with a KTM 520 EXC who is coming in at 110 kilos and is almost 195cm tall..... It's going to have to be a Progressive for his size and Extreme Riding Off Road. The other side of the "Progressive spectrum" is our fellow Thailand natives who need to have a PCX150 to commute solo everyday and can also "Double Duty" as a "Family Wagon" and grab up the wife and kiddies after school and work...... This is truly where a Progressive Spring is needed.

    Ill assume you ride the street, on that Liter Bike we would have suggested a Dual Rate w/remote resivoir in Rear and dual rate front spring set to balance out the front squat...... Marzzuchi would have been my first suggestion, but as they are now out of business, we would recommend Ohlins or Wilbers.

    Listed in the Below Pic are typical of the 3 springs available to power sports. Types.

    Cheers
     
  5. Brad
    Yes, its a Ducati GT1000 street bike. The YSS twin shocks have piggyback reservoirs, 30 click comp, 60 click rbd, 10mm height adj, and preload adj.
    They came with 46-20-30-220 springs which is 46mm diameter, 220mm long, 20nm to 30nm springs.
    I need around 30mm preload to get the correct rider sag, (around 1/3 of available travel measured at the rear axle)
    However, on bigger hits (rough sealed roads/potholes) it very harsh, even with comp and rbd all the way out.
    I did try heavier springs, 46-25-35-220, which required less preload to attain correct rider sag, but they were even harsher on bigger hits.
    My thinking is linear rate springs, around 25nm, would require less preload to attain correct rider sag, and would be less harsh on bigger hits, compared to 20-30nm progressives.

    On the front are OEM Marzoochi forks (originally non adjustable) with Andreani cartridges, 8.8nm linear rate springs, comp/rbd/preload adjustable.

    My KTM 500 xcw runs the OEM linear rate spring on the PDS monoshock which I'm happy with, although some suspension guru's recommend a progressive spring.
     
  6. Bill,

    You're thinking is right on! The Rule of thumb is if [ the Static Sag is good but rider Sag out.... Too soft] [ If Static Sag low to 0 and Rider Sag is in, too hard]

    Again, The sags are difficult with Progressive Springs.....but Progressives from 20 n/mm to 30 n/mm X 2 is making my butt hurt. .....and it's your bike were talking about. Whats her weight (Curb) and whats your weight? (ATGATT)

    Forgive me, but it's not as though we have many GT1000's come through, so I cant shoot numbers off my head.......But let me take a peek and see whats offered for The Mighty Ducati GT. The fronts seem a bit light to me at 8.8n/mm .....are the cartridges open, closed. or pressurized?

    Remember Andreani is a PARTS COMPANY.....not a suspension company. Once they start manufacturing their own parts and (The research and development spent) systems, as well as winning a lot of races, or around for half a century with proven results..... then, I'll think about being a service center for them.

    Once Andreani or anyone Modifies anyone elses Components..... the warranty as well as the liability is gone from the manufacturer...... buyer beware.

    I'll try to figure out the mail or message system..... as were probably boring everyone else.

    Brad
     
  7. Brad
    PM sent.
    Check your Alerts or Inbox, top right-hand of forum webpage.
     
  8. Well I did source some 25n/mm linear rate springs from YSS. They are 20mm shorter than the standard 20-30n/mm dual rate springs.
    However, to achieve the same rider sag as the standard springs, the installed length is only 10mm shorter.
    Color choice was red, unless I ordered 10+.
    Its moderately improved the ride to what I was aiming for. A bit more compliant without bottoming out.



    20170901_103525.
     
  9. Cannon Racecraft in the US will make you any spring your heart desires at a reasonable cost
     
  10. Hoghead,

    We have used Cannon in the Past.... Its rather pricey, and typically for either, OEM that is not available anymore or ATV.

    Factory Connection also has a great selection that has got us out of many binds with On/Off road and dirt bikes for really big riders standing 6ft 6in. and 250lbs.

    Cheers
     
  11. Bill,

    Awesome Bike! Classic....

    For that beauty and riding pleasure, we probably would order specific Dual Rate Front springs, mixed you up some double secret synthetic viscosity front fork oil, and the latest finishing techniques for less friction.

    Im curious to hear about your Static Sag and Rider Sag that You came up with from the build.

    Since you have almost a 1 to 1 ratio on the rear suspensuon (Linkless).... Swingarm travel, Pre/load and spring rates are Paramount on that bike.....

    We would also recommend a positive squat on her as well.

    When your ready ..... we now do pick up and delivery in the greater Bangkok area.

    Cheers.
     

    Attached Files:

  12. Brad, I've aimed for the most compliant ride for touring around Cambodia, Thailand, and Laos.
    Starting with ohlins streetbike sag recommendations and tweaking it from there. Orings on the shock shafts and a tie wrap on the fork to monitor/make sure there's enough preload to prevent bottoming out. Then tweak the front to rear geometry with either the threaded yoke height adjuster on the YSS shocks or moving the forks in the triples. The end result is I run sag to the higher end of Ohlins numbers and frt/rear comp and rebound to the soft side. I have around 10mm of unused shock shaft travel under normal riding conditions and ~ 30mm on the forks. The rear will still bottom out over larger potholes though.

    The baseline Ohlins streetbike sag recommendations I used are
    :Static sag
    Front 20-30mm
    Rear 5-15mm
    :Rider sag
    Front 30-40mm
    Rear 25-35mm
     
  13. I was thinking of custom made springs.
    Thanks for the Factory Connection reference and will check them out next time I am int he market for something special
     
  14. Ass up or down?
     
  15. Morning Bill and all my forum hommies..

    Blasting out for a long holiday in Burma....

    Rreal quick note..... When we Squat and Sag a bike properly: we need a static stand and a couple of staff or friends helping us to produce accurate readings.

    The ty rap method is good for quick visual refference for your preload add or subttact process.

    As far as the "Ohlins" Street Sag guide or recommended factory settings: That became moot with the YSS rear shocks... Mixing and matching of Brands easily confuses the equation.

    Typically when we see companys that focus on the rears and not the front end products a" Disparity " takes place and one can never truly find the "sweet "spot" from initial to fine tuning.

    WITHOUT SEEING YOUR BIKE IN FRONT OF US AND THE WAY SHE SQUATES AND READING YOUR SAGS....

    All I can say is (if your readings are fairly accurate and without knowing your Spring rates and stroke)..... It seems you have produced a negative squatted bike on a machine that should be positive.

    We reopen again on Friday....think thats the 9th. Give us a call....

    Cheers
     
  16. I understand static and rider sag in relation to spring rates and range. I also understand the effects of having one end to the bike higher than the other.

    What I do not understand is your term positive squat - please clarify
     
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