R-1 shock on a Versys

Discussion in 'Technical' started by Hoghead, Dec 23, 2011.

  1. Hoghead

    Hoghead Ol'Timer

    There recently has been some development work in both the UK and USA in mounting a R-1 shock on a Versys, using a custom made spring. One could use a standard Racetech spring with collars, but no point, when you can get a spring made for your weight and wound to fit the shock without collars at a better price. I will go for a progressive rate starting at 13.8 kg/mm to maybe 17-18 kg/mm over 100mm with a 150 mm range.
    These guys are racing spring gurus - not the greatest website but good kit:
    http://www.cannonracecraft.com/catalog3/index.php
    Constant rate is 110 USD custom made to fit the R-1 shock

    I know that an 06-08 R-1 will work and that a 2010 will not. Not sure about any other years.
    The 08 has both low and high speed compression damping

    I just bought a used R-1 shock with 4500 miles on it for 35.00 USD on EBay and am now getting the spring made.
    Will report back when the project is finished, but from what I understand it works very well, and the price is right at 150.00 USD for the finished unit plus freight. Machine work is required to bore out the mounting eyes from 10 to 12mm but machine shop work is cheap here. Not sure if one could simply push out the R-1 bushes and push in the Versys parts as the shock eyes are the same size (I think)

    This combined with my fork re-valving project should have the Versys well sorted, and tuned for my bulk and style on our roads.
     
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  3. Hoghead

    Hoghead Ol'Timer

    Got this mounted yesterday and it is bloody brilliant compared to the stocker. And to think that I bought the Versys due to the improved suspension over the ER6

    As noted in an earlier post, spring rate is critical and needs to be chosen with an eye to ones weight, riding conditions, and riding style. Using a rather unscientific logarithm, I calculated that a 13.8 Kg/mm spring would be right for my 76 Kg + gear weight. Granted that the design Engineers have to pick a compromise, but it sounded a bit soft given the specified stock rate of 16 kg/mm. To play it safe, and to account for baggage, I bought a progressive rate 13.8 - 16 kg/mm. I never carry a passenger and in retrospect if I was to do this again, I would buy a non-progressive 13.8 kg/mm rate now that I have ridden the bike.

    The clever Engineers at Kawasaki, using geometry and how the shock is mounted to the swing arm, have designed in a rising spring rate of 9.5%. (I suspect that the popular lowering kits for the shock f*&k up this geometry.) Not only is geometry a factor, but it appears that the stock spring is not linear per the specifications, and there is a progressive rate from 15.8 - 19.1 kg/mm over the 55mm range. All this tots up to a 21% rising rate at the wheel which makes me all the more comfortable with a constant rate spring given my riding conditions.

    If you are a bit lighter a spring from a Yamaha Roadstar is an exact fit to the R-1 shock and 13 kg/mm. These can be had very cheaply on eBay.
    I had my spring made by Cannon Racecraft in the USA as I have used them in the past with good results. Cost was 110 USD for a constant rate and 175 for a progressive rate. including powdercoating in your choice of colour. You could use a cheaper off the shelf 7 inch Ebiach spring but will need an adapter collar for the shock.
    Unless you are a featherweight you will find that the stock R-1 shock ranging from 8 - 9.4 kg/mm depending on the year, will be too soft.

    After much marketing bafflegab and even stating that their Engineers used proprietary measuring nomenclature, and I would not understand the physics, Hyperpro Holland finally relented and gave me their Versys spring rate as 15.9 to 29.7 Kg/mm. Note that initially it is virtually the same as the already stiff stock spring and progresses upward from there to really bloody stiff. I fail to see how this is an improvement unless the bike is fully loaded and dual up all the time and even then I suspect that it is oversprung.
    Funny how this is the leading spring upgrade in Thailand, or is there just nothing else available and no knowledge base to have the right one made?

    Next to the spring, the valving is the key thing to shock performance, and I am relying on the stock R-1 valving. Today I am re-valving the fork with Liams help. Once that is dialed in it will be easier to evaluate the R-1 shock valving in a Versys application. How it compares to an Ohlins would be interesting, but I suspect that is is better than the oversprung Hyperpro. I would love to ride all 3 shocks + the stocker back to back

    All in all this is a not too difficult and a fairly easy and cost effective mod.
    Cost was about 10,000 B and could be done for less using a constant rate spring, or way less if you are light enough for the Roadstar spring
     
  4. trevbart

    trevbart Ol'Timer

    Good job Robert!
    BTW I happen to have a new Ohlins 14 kg/mm spring if you would like to try it, only problem the ID is 58mm (so it will only work with the 55-58mm spacers)
     
  5. Hoghead

    Hoghead Ol'Timer

    I wish that I would have known that before I went and had one custom made and imported - just my luck
    The 58mm Id is not an issue and as you say a spring collar will solve the issue, and the 6mm of preload as a result of the collar will be just about right for a rider at 76 ish Kg
    What is the unloaded length?
     
  6. trevbart

    trevbart Ol'Timer

    It is just over 7 inches, 182mm to be more exact. Perhaps useful if anyone else doing this mod. Shipping on the adapters would be much less than a spring!
     
  7. Hoghead

    Hoghead Ol'Timer

    That would likely work just fine without grinding the ends, as one most likely will need some preload on the spring anyway in excess of the 6mm provided by the collars. In any case it can be ground here for 450 B so no big deal
    Collars can be machined easily and cheaply as well.

    A good buy for someone doing the mod
     

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