Intiminator Compared and modified

Discussion in 'Japanese polycylindered adventure bikes' started by AceRider01, Jul 18, 2009.

  1. Ladder106

    Ladder106 It's a short cut, really

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    In an effort to maximize the Intiminator Kits for the Transalp and Africa Twins, Ricor had me try a softer spring in my Transalp along with the same Intiminators that are used in the Kawasaki KLR 650.

    The standard Transalp front spring is .5kg/mm with the later euro-models going up to .6kg/mm in an effort to curb fork dive problems.

    The springs I'm using are .43kg/mm with the standard KLR Intiminator.

    This set-up is about 40% better both on and off-road than the standard .5kg/mm spring with my modified Intiminators.

    My analysis is that the softer spring allows more fork leg movement from less of an input and also allows faster fork leg movement thus allowing the inertia valve to "open" sooner and farther. This is what we both tried to mimic with our modded holes.

    So....i'd encourage you to try the softer springs. The static-to-rider-sag ratio is just a bit "off" but I don't look at that as an unbendable rule anyway.
    #41
  2. AceRider01

    AceRider01 Fully Loaded

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    Did you try to softer springs with an unmodified intiminator to see whether the same problem (high veloity damping) occurs? Riccor seems to think the high velocity damping issue completely disappear with a softer spring!

    I could imagine a dirt road orientated rider would always find softer springs better.


    EDIT: sorry re-read post - so you are saying that using 0.43kg spring with an unmodified intiminator is 40% better than 0.60kg/mm spring with modified intiminator - please elaborate. You should try the modified intiminator with 0.43kg spring and see what happens? any downside with the 0.43kg spring? - bottom out / brake dive issue/ relationship with rear issue?





    #42
  3. Ladder106

    Ladder106 It's a short cut, really

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    Using the lighter spring with my modded valve is the next logical step.

    Brake dive was worse with the lighter spring but not as bad as stock. No bottoming despite running about 20 mph perpendicularly across some 10-12 inch. high hard rutted ground. Onlly 1 small jump with about 18 in of air on both ends.

    The rear shock is standard and rubbish compared with the front. Waiting for the Ricor Transalp shock for the rear. With that, I'd say that the rear feel was unchanged.

    I am, admittedly, a dirt oriented rider. However the lighter spring/standard Intiminator did feel better through bumpy asphalt corners. Not significantly better but there was a more stable feeling.

    I was posting to encourage your lighter spring trial. I think it's a good direction to go.
    #43
  4. AceRider01

    AceRider01 Fully Loaded

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    Ladder106

    #44
  5. AceRider01

    AceRider01 Fully Loaded

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    -re measure my front sags - 32mm Static sag (free sag) and 43mm of rider sag... this after setting a preload of about 10mm.

    I could quite remember the rear, but i think it is about 11mm of static sag with 43mm of rider sag, when riding solo without much luggage.
    #45
  6. Wanna Ride

    Wanna Ride Adventurer

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    The good news is I contacted a friend with a 650 V-Strom and a set of Intiminators he has not installed yet, and we will get together for testing and installation of Intiminators. He goes by G-Dog on this forum. The bad news is it may take a month or two before our schedules match and can get it done. He weighs 200 lbs with about 1 or 2 years riding experience and wants to set up the bike to ride both on highway and easy off road. So I am open to suggestions on where to start.

    AceRider - we are going to have to agree to disagree how the Intiminators work. To me, they work as advertised. I haven't given up the "debate" but I do have some ideas you may want to try. I will assume you have the riding experience to test ride safely after major suspension changes.

    Question - are you sure the washer you added is not affecting how the Intiminators function? Is the washer blocking oil flow through the ports? Is the washer blocking oil flow to or from either circuit because it is too close to the coils of the main spring? Is the washer preloading the springs the inertia collar floats on and reducing the ability of the inertia collar to react properly? I don't know the answers, just wondering.

    I have no idea if any one has ever tried the following idea. I did not ask Ricor about it. You have to decide if it is worth the work.

    Take out the shim stacks, replace the Intiminators and test ride. Leave the inertia valve intact. This will convert your forks back to function similar to damper rod forks, except with the inertia valve. The rebound damping will remain the same, and the spring will still support the weight of the bike. Compression damping will get a lot softer and you should get more fork dive. If the bike is safe to ride, you should be able to test at different bumps and speeds.

    Then take out the Intiminators and increase the preload spacer length to keep rider sag the same as with the Intiminators. Also keep oil height the same. Test ride. This will reduce fork compression damping as much as possible with the current spring, damper rod compression holes, stiction, oil weight/height, preload etc.

    This will tell you a few different things. First it will give you a better feel what the two different circuits are actually doing. The second is, if you cannot get high fork shaft speeds due to low compression damping without the Intiminators, you will never get high shaft speeds with the Intiminators. In other words, with the Intiminators out, your compression damping should feel way too soft. If it doesn't, your problem is something else besides the Intiminators. Hopefully, this experiment will give you better insight for further tuning to get the compression damping where you want it.

    When I first set up suspension, I set it up so it is too soft. Then I stiffen it up from that point only as much as needed. I try to use the point of "too soft" as a starting point. From that point, the only direction to go in is harder. Obviously, if the suspension is way too soft to begin with, you need to go in the other direction.

    I bought my Harley Sportster/Roadster 3 years ago on a whim. I hadn't ridden any Harley in 15 years. I showed up at the dealer when they were having a big sale and bought it. I had no idea how bad their suspensions were. I didn't care too much because I weigh 260 lbs and have to redo the suspension of any bike I ride.

    The first thing I did was order Race Tech emulators and straight rate springs. I drilled the damper rods and put in 20 w oil, all by their recommendations. I started to loosen the spring adjusters, and then loosened them again and again. They got so loose I figured they weren't doing any thing, so I took the emulators out completely. Then I changed to softer Works Dual Rate fork springs. Then I reduced fork oil from 20w to 10w to 5w. With the 5w fork oil, I started to get some undamped wheel hop over braking bumps. Not good, so I went back to 10w, still with the drillled compression damping holes. I rode it for over 2 years like that, until the Intiminators came out. I didn't realize how over damped the forks were until I found the point where they were under damped.
    #46
  7. AceRider01

    AceRider01 Fully Loaded

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    See my comments

    quote=Wanna Ride]The good news is I contacted a friend with a 650 V-Strom and a set of Intiminators he has not installed yet, and we will get together for testing and installation of Intiminators. He goes by G-Dog on this forum. The bad news is it may take a month or two before our schedules match and can get it done. He weighs 200 lbs with about 1 or 2 years riding experience and wants to set up the bike to ride both on highway and easy off road. So I am open to suggestions on where to start.

    AceRider - we are going to have to agree to disagree how the Intiminators work. To me, they work as advertised. I haven't given up the "debate" but I do have some ideas you may want to try. I will assume you have the riding experience to test ride safely after major suspension changes.

    Question - are you sure the washer you added is not affecting how the Intiminators function? Is the washer blocking oil flow through the ports? Is the washer blocking oil flow to or from either circuit because it is too close to the coils of the main spring? Is the washer preloading the springs the inertia collar floats on and reducing the ability of the inertia collar to react properly? I don't know the answers, just wondering.

    when you disassemble the intiminator you will see that washer does absolutely nothing except to give some extra "meat" for my claw tool to hold on too - the valve never touches it - it sits on another "washer" (i dont what it would be called) which intiminator uses to stop the inertial valve (gold sleeve) pass certain point on the shaft - they are both held down by the top bolt. - The orifices open side way - so the oil "squirt" sideway - i think in the almost empty of space of 43mm fork tube interior, it would make very little differences if at all - you will see what i meant when you disassemble the item - a little hard to describe in words

    I have no idea if any one has ever tried the following idea. I did not ask Ricor about it. You have to decide if it is worth the work.

    (1) Take out the shim stacks, replace the Intiminators and test ride. Leave the inertia valve intact. This will convert your forks back to function similar to damper rod forks, except with the inertia valve. The rebound damping will remain the same, and the spring will still support the weight of the bike. Compression damping will get softer and you should get more fork dive. If the bike is safe to ride, you should be able to test at different bumps and speeds.

    BE prepared that the bike will be extremely soft on damping - i say that you are essentially riding on springs only.

    The system becomes essentially the same as standard - except that you are now using 5wt oil (instead 10-15wt oil)- so i would say low velocity damping would be VERY SOFT compare to standard - high speed compliance would be softer than standard because oil is thinner - when you take out the shims all the oil will flow pass the intiminator through the holes at the bottom of intiminator body where the oil was design to push the shims open. The intiminator will add no /or extremely limited resistance to oil flow if any.

    The intiminator is useless in that situation and so is inertial valve - because the oils will simply flow pass the holes where shims would normally cover whether or not the inertial valve is activated.

    have a look at the bottom of intiminator - the area of of 6 holes (not the one in the middle-that's the shaft) is so great that the oil would just choose that path and that no resistance would be offered by the intiminator[​IMG]




    (2) Then take out the Intiminators and increase the preload spacer length to keep rider sag the same as with the Intiminators. Also keep oil height the same. Test ride. This will reduce fork compression damping as much as possible with the current damper rod compression holes, stiction, oil weight/height, preload etc.

    I think you will find the feel very close to if not the same as your step above as (1)


    This will tell you a few different things. First it will give you a better feel what the two different circuits are actually doing. The second is, if you cannot get high fork shaft speeds due to low compression damping without the Intiminators, you will never get high shaft speeds with the Intiminators. In other words, with the Intiminators out, your compression damping should feel way too soft. If it doesn't, your problem is something else besides the Intiminators. Hopefully, this experiment will give you better insight for further tuning to get the compression damping where you want it.

    I see what you are trying to get at - i could just take out intiminator as in step (2) you outlined as this would be practical min flow on the high speed circuit - so at least i know where the limit is for the high speed circuit -

    mine is already drilled out -the better comparison would be using a unmodified intiminator to test out the amount of restriction on the high speed circuit on the unmodified intiminator.

    If you or your friends were to do that BE EXTREMELY CAREFUL, because you would essentially be riding on nothing too much more than springs.


    When I first set up suspension, I set it up so it is too soft. Then I stiffen it up from that point only as much as needed. I try to use the point of "too soft" as a starting point. From that point, the only direction to go in is harder. Obviously, if the suspension is way too soft to begin with, you need to go in the other direction.



    I bought my Harley Sportster/Roadster 3 years ago on a whim. I hadn't ridden any Harley in 15 years. I showed up at the dealer when they were having a big sale and bought it. I had no idea how bad their suspensions were. I didn't care too much because I weigh 260 lbs and have to redo the suspension of any bike I ride.

    The first thing I did was order Race Tech emulators and straight rate springs. I drilled the damper rods and put in 20 w oil, all by their recommendations. I started to loosen the spring adjusters, and then loosened them again and again. They got so loose I figured they weren't doing any thing, so I took the emulators out completely. Then I changed to softer Works Dual Rate fork springs. Then I reduced fork oil from 20w to 10w to 5w. With the 5w fork oil, I started to get some undamped wheel hop over braking bumps. Not good, so I went back to 10w, still with the drillled compression damping holes. I rode it for over 2 years like that, until the Intiminators came out. I didn't realize how over damped the forks were until I found the point where they were under damped.[/quote]
    #47
  8. Wanna Ride

    Wanna Ride Adventurer

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    I couldn't sleep, so I got up and reread this thread. AceRider and Ladder106 have really done some amazing work not only figuring out how the Intiminators work, but also documenting some fairly extensive modifications. Again, I will state that I have not done any work on a V-Strom, so my responses are more general and based on work with other bikes and converstaions on other forums, and some with Ricor.

    AceRider, after thinking about it, you are correct that removing the shim stack will let oil flow through the body unrestricted and therefor not give any indication of what effect the Inertia valve is having. Perhaps the better thing would be to stack as many shims as possible in the shim stack so it CANNOT open at all, and that would force all the oil through the Inertia valve so you could feel what it is doing when working by itself.

    Then test rides in 4 different configurations, 1 Intiminators removed, 2 shim stack closed off with inertia collar free, 3 inertial collar jammed closed so it cannot open with shim stack intact, and 4 normal operation, would give you a definite feel for what the different circuits are doing. I am not really expecting you, or any body else to actually do this. It is the only way I can think of to allow a rider to actually feel the effects of the different circuits while riding.

    The next good question, and I think you started to raise it with Ladder106, is what will the overall effect be with your modified Intiminator and welded rebound damping holes when combined with softer springs? It is quite possible the stock spring would be too light, maybe the .80 would be better.

    I brought this quote up because it represents the "normal" confusion surrounding the Intiminators.

    Damper rod and conventional cartridge fork system work due to velocity of oil. More damping is produced by higher velocities, higher viscosities, or by increasing resistance.

    Damper rods have a relatively small range of oil velocity where they would work effectively. Oil is forced though holes in the damper tube. Below that ideal range, they did not dampen much. Over that ideal range they would over dampen until they reached the point where the oil just blew through the seals.

    Cartridge (shim stack) forks are able to provide damping control over a wider range of oil velocities. The shim stack could be selected to let just a little oil to flow through at low speeds producing low speed damping, AND to allow a lot of oil to flow through at high speeds producing high speed damping.

    "Speed/velocity" refer to how fast the lower fork tube must move in response to bumps and dips in the roed. It is also called shaft speed.

    In both cases of damper rod and cartridge rod forks, the resistance to oil flow (damping) occurs whether the lower fork tube is moving up, or if the upper fork tube is moving down, and the damping velocity dependent in either case. In other words, the velocity of the oil due to either, or both, fork movements determines the amount of damping provided. (Forgive the oversimplification.)

    Because of the 2 different circuits, the Intiminator CAN tell if the upper fork is moving down, or if the lower fork is moving up.

    Situation 1. If the wheel is on a smooth surface (not moving up or down), and you grab the front brake, the Inertia/wheel circuit remains closed because the Inertia collar does not move in relation to the ports in the barrel/body. All the oil flows through the shim stack/chassis circuit to resist fork compression/fork dive. Referring to this as the "slow speed circuit" is common.

    Situation 2. NO braking, just constant motorcycle speed. If the wheel hits a bump and starts to move up, the ports in the body/barrel move above the inertia collar and oil starts to flow through. This Inertia/wheel circuit becomes a high (shaft) speed bleed. It blows off high speed compression damping. So much high speed compression damping is blown off, the spring itself, fork stiction, unsprung weight, and air chamber/oil height become important factors in resisting fork compression.

    There is some debate how much oil also flows through the shim stack in this situation. The less oil that can flow through the shim stack, the better the chassis remains supported, meaning less fork compression/dive due to the weight of the bike/rider.

    Situation 3. Hitting a bump while braking hard. The chassis/shim circuit resists fork compression due to the weight of the bike/rider falling down while the Inertia/wheel circuit allows fork compression due to the wheel moving up.

    The real debate is what is happening in situation 3. In normal operation of the Intiminator, you want to maximize oil flow through the Inertia/ wheel circuit, but minimize the oil flow through the shim stack . However, if the tire hits such a big bump that the oil cannot get through the ports of the Inertia valve/wheel circuit fast enough, it has nowhere else to go except through the shim stack/chassis circuit. Finding the correct balance of oil flow through the different circuits in situation 3, and also matching spring rate is the key to getting the Intiminators to work they way they are supposed to.

    AceRider enlarged the Inertia valve ports in attempt to maximize oil flow. That seems to have occurred enough to notice it while riding, even though Ricor said the limiting factor was the inside diameter of the barrel.

    AceRider, did you stiffen up the shim stack or loosen it up? My brain is somewhere else pretending to be asleep at the moment, and I really can't remember. I think you stiffened up the shim stack. I also seem to remember you saying you felt there was too much damping over medium to large bumps. Should you have loosened the shim stack to get better bump compliance and just live with the resulting extra fork dive.????

    Can you summarize what you did and why?
    #48
  9. AceRider01

    AceRider01 Fully Loaded

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    response are as below in yellow

    #49
  10. Wanna Ride

    Wanna Ride Adventurer

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    If Ricor set up the Itiminators to work for someone with your skills and experience, they probably wouldn't work for 90% of the other V-Strom riders who can stay with the stock fork spring.

    Is it possible to drill out the inside diameter of the barrel tube to get more oil flow? If it matches your current spring, it may not work with a lighter one.

    I finally figured out unsealed means unpaved road.
    #50
  11. AceRider01

    AceRider01 Fully Loaded

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    Wanna Ride,


    :evil yep, one of those term australian use - wasnt even aware it was an issue.
    #51
  12. Wanna Ride

    Wanna Ride Adventurer

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    What next? My guess would be to try to make everything lighter/softer. Less preload, a lighter fork spring, make sure the oil level or something else you are not aware of is not interfering with fork travel. If the standard settings are not working for you, try something else. I have read several reports on different bikes where just reducing preload made a big difference with the Intiminators.

    Tune the bike to match the Intiminators instead of trying to tune the Intiminators to match the bike. Reduce oil height 1/2 Inch at a time. If you get more travel, you had too much oil. Then reduce fork spring preload until the forks bottom out over the biggest bumps you ever hit. Then add just enough oil to prevent bottoming. That will be as soft as you can go with your current spring and oil viscosity. Soften up the shock in small steps and test ride.

    I don't think removing the Intiminators for a test ride will be as dramatic as you think, especially with the rebound hole welded up. Start at slow speeds and small bumps, and increase your speeds and bumps as you get a feel for how it handles. I have ridden bikes with totally worn out suspensions. It becomes obvious very soon you should not try to go any faster.

    Here is an example where overlooking a small detail and the wrong spring made the forks handle poorly. A friend of mine sent the (I think) Showa forks off his Ducati Monster to a well know aftermarket suspension shop here in Southern California for new springs and revalving. It came back even worse than before. Way too stiff and way too much stiction. We took the forks off and took them apart. They did not lube the seals and the stiction was incredible. We were both surprised how much stiction was reduced just by lubing the seals. But the spring was still too stiff. He took the forks back and made them put in a spring 2 steps lighter and redo the valving to match. Much better.
    #52
  13. AceRider01

    AceRider01 Fully Loaded

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    Wanna Ride,

    If you re-read my posts - sorry there are many and very long- but you will see that i have done just about all that you have mentioned. I agree, if you could, do all your own work - no body else is going to take care the small things as carefully as you would yourself.

    stiction / forks being straight- there is an easy way to check - fork caps off - bike supported - lift the wheel up and down - you can feel the stiction then - worst case scenario - you can lift the front of the bike up without the forks moving much. To check if the fork is set straight in equal vertical distance from the triple clamp, mount the forks as accurate as possible, take the wheels off, re insert the front axle - you should be able to turn and tighten it without too much effort using just your hands and no tools.


    As in regards to the preload - they do not change the spring rate - i am happy with with my preload and the range of fork travel that i use.

    Fork oil level only really effects the last 1/3 of spring travel - the progressiveness of effective spring rates as one approaches bottoming out. Oil lock piece in the DL650 fork will stop real bottoming out in 99% of cases anyway.

    If you use all but the last 35mm of travel in aggressive riding on normal roads you should be okay. Braking very hard until the front wheel lock or braking very hard over bumps until the front wheel hop and skip should send you to the last 20mm. The last 20mm is for all the unkown out there. Racers on track will try to use all but the last 5-10mm - not suggested on street riding.


    The thing is just about everything else was more or less right except for the high velocity damping which was way off. Enlarge the bleed holes - problem solved. Everything else i done afterwards is about fine tuning.

    Of course when i get my hands on the original springs and maybe some seriously too soft springs, i will try them and see what the effects are -

    One have to remember, in the pursuit of getting better high velocity compliance, you dont introduce another issues into the system - such as too soft of a springs on handling. Damping should work with springs not to over-compensate too soft or too hard of a springs.
    #53
  14. Wanna Ride

    Wanna Ride Adventurer

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    Well ... there are exceptions to every rule:

    Sport Rider

    Too much preload can require more force to start the spring compressing and feel stiffer to the rider. Reducing preload may make the initial movement of the springs feel softer to the rider.

    Heavier spring rates will also feel stiffer to the rider. Don't confuse the two situations. Stiffer forks need less compression damping and more rebound damping in addition to less preload. Which is what you found with your Intiminator modifications.

    Too much oil can cause hydrolock and stop fork movement anywhere in the travel. Ohlins used to have their fork manuals posted and they had a graph that indicated this. My link doesn't work any more.
    #54
  15. PeterW

    PeterW Long timer

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    The fact that the DL's have progressive (well dual rate) spings also messes with "preload" has no effect other than ride height "rule" as well. Dial in more preload with progressive springs and you are starting at a higher spring rate. I'll admit it's a small change, but it is a change.
    #55
  16. AceRider01

    AceRider01 Fully Loaded

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    comments below

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  17. Wanna Ride

    Wanna Ride Adventurer

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    Some guys, especially beginner riders, can have one aspect of their suspension set up way out of normal ranges without realizing it. Then they totally confuse themselves by trying to adjust another aspect and end up making things even worse.
    #57
  18. AceRider01

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    still doesnt answer my question - so what was the rule then? and what was the exception to any particular rule?
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  19. skirider73

    skirider73 Backroad Hack

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    Acerider1 - I've been following your adventures on several site related to dialing in the Intiminators. Great work. Ricor should put you on the payroll.

    My take is that these were designed for a stock spring on the Vstrom. The inertia valve was created to fix brake dive, which can also be fixed by heavier fork springs. One a heavier spring was introduced, the design really shows its limitations and plain old doesn't work in its current "standard" form.

    I'm running Sonic .9's with the Amsoil 5wt and Intiminators. I started with .95's per Sonic's website - too stiff. The front end was rigid as hell. The .9's are better - but I still have too much high speed dampening. I'm running 13MM under the caps with adjusters backed all the way out. This yields a nice 43MM sag. Based on standard suspension theory, this is the correct spring for me.

    The Intiminators with stock springs felt the best so far; however, sag was in the 55MM range, which I feel lowers the front end too much and causes some ill handling, including too fast turn in. Putting more preload under the caps brings sag back into the 43 MM range, but turns the ride to crap.

    My weight and riding style are similar to yours, except my roads are choppy New England roads.

    Have you tried the 2.5 wt Shock Therapy oil? That would increase flow across all circuits in the Intiminator; and with your rebound holes shut would have a lesser effect on rebound dampening.

    The RT emulators seem to be tuned to a given spring; the Intiminators require a spring to be tuned to it. And right now, the only spring that seems to work is the progressive stock Vstom spring.

    I'm debating on what to do next. I may purchase some Gold Valves and call it a day. The allure of the Ricor product was to keep the stock rod holes intact.

    I'm pretty sure based on my reading that you haven't played with stock Wee springs yet (my bike is a 2007). I'd be willing to send you my stock springs if you are interested in playing with a softer spring. I don't know what postage is like to Australia, but I've got my Sonic boxes still and shipping is from 03303. Shoot me a PM and we can work out details.

    Thanks again for your hard work. There are lots of Vstrom riders tuning their bikes based on a select few's work. I'm one of them :D

    Jay
    #59
  20. Wanna Ride

    Wanna Ride Adventurer

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    Pick a rule, any rule, and someone will come up with an exception. It's up to the reader to determine what applies to his specific situation and what doesn't. For the most part, I prefer to consider "rules" more like guidelines. Mainly because guidelines imply there is a range of values that may be used. The best suspension tuners understand how all the different parameters and their range of values interact and affect the overall result. The not so good tuners think some specific parameter is written in stone and then drive themselves crazy trying to make everything else work.

    The oil height not having any, or much, effect, until the last 1/3 travel is a good guideline, but is not true in all cases. One reason I say that is because oil height may not be where the rider thinks it is. I have seen oil levels from the factory (different brands of bike), and from aftermarket suspension companies, that is not where the manual says it is supposed to be. I have seen different oil levels in each fork, despite claims to the contrary of the aftermarket company who did the rebuild.

    Some guys also make the mistake of not measuring correctly, not bleeding correctly, don't understand changing to a different spring that puts more coils under the oil level, or adding any after market valve body tends to raise the level, etc, etc. Another consideration is the diameter of the fork tubes. Fork tubes with smaller diameters tend to push the oil level up quicker than smaller diameter fork tubes. So what may be a good quideline for one bike may not be so good in a different bike.

    Well, it actually depends on the actual spring rates, how much travel the spring stays in one spring rate, and how long the transition zone is between the different spring rates, and how much you change the preload, how close to topping out the forks are, and how all the other parameters interact with the preload change.

    The technical specs for a dual rate spring must include the initial rate, the final rate, the length of travel the spring stays in each rate, and the length of the transition zone between the 2 different rates.

    For example, if the spring stays in the initial rate for the first 2" of fork travel, adding 1/2" preload may appear to leave 1 1/2" travel in the initial spring rate. Well, not quite, read on. The change should be noticeable, probably only raising the ride height if the fork tubes are not topped out.

    If the dual rate spring has only 1" of travel where it stays in the initial rate, and then you add 1 1/2" preload you will likely feel a much greater effect, especially if the forks top out. It is likely the initial coils will coil bind, bottom out against each other. If that happens, the only spring rate you will feel is the harder final rate. How much stiffer it feels while riding will depend on much difference there is between the different spring rates.

    A spring may have a progressive rate that slowly increases throughout its travel instead of distinct transition zones. In that case, if, or when, the fork tubes top out, adding preload will increase the spring stiffness a bit because the additional preload forces the spring into a lower part of the travel. If the fork tubes are not topped out, the result will be raising the front end.

    The effect of adding preload will depend on how close to topping out the forks tubes are. They may not be topped out while measuring rider sag, but that may change while riding. Regardless, calculating the actual response to changing preload of a dual rate or progressive rate spring is rather difficult. Test riding is probably the best way to determine which preload setting works best in your particular case.

    Using the point-of-view of "guidelines" rather than "rules" in the overall picture, it is important to understand how changing preload, spring rate, compression and rebound damping, oil height and viscosity, chassis pitch, rider weight, style, road conditions all interact. For example, it is possible way, way, too much oil height or improper damping interferes to the extent changing preload cannot provide the change you were expecting.

    Works Performance does offer a dual rate fork spring kit which is composed of two different springs. One spring has a metal tube in it to limit it's travel and determine where in the travel the combination transitions from the initial to final rate. In addition, you can change one or both springs to get a very broad range of adjustments. They do have a fork spring listed for 02 and later V-Strom 1000. I don't know if it is actually a dual rate spring or not. I don't know of anybody who has used one in a V-Strom. However, it does add another degree of complexity and difficulty in tuning the forks. It is an option if somebody cannot find a spring to their liking. I have a Works Dual Rate kit in my Harley Roadster and it works very well. Be warned, I did not like the Works recommendations and experimented until I found the combination that worked best for me. That was before the Intiminators.

    http://www.worksperformance.com/html/street.html
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