Project WeeStrom 7.5

Discussion in 'Japanese polycylindered adventure bikes' started by OhioPT, Apr 23, 2011.

  1. OhioPT

    OhioPT Adventure Wannabe

    Joined:
    Sep 15, 2007
    Oddometer:
    1,134
    Location:
    Columbiana County, OH
    What Is It?
    A 2004 DL650 with 7.5 inches of front and rear suspension travel, and 7.5 inches of ground clearance.

    [​IMG]

    [​IMG]

    [​IMG]

    What I Did
    I modified the damper rods of my front forks to gain 40mm of front suspension travel, and to increase the ride height. My front ride height increase is actually 27mm over stock, with the proper rider sag dialed in and accounting for the rake of the chassis. Custom springs and spacers were necessary to achieve the proper sag. I also have “widgets” installed in the forks, which basically act like emulators to control damping. These have no influence on ride height or overall suspension travel though.

    Stock Fork, Full Compression Travel Measured:
    [​IMG]

    Modified Fork, Full Compression Travel Measured:
    [​IMG]

    Modified Forks Installed:
    [​IMG]

    I also raised the rear of the bike with a custom made longer travel shock from Cogent Dynamics. This shock provides 41mm more travel than stock. The actual rear ride height increase with me in the saddle is 29mm with the suspension sag set correctly, which maintains the bike’s handling balance.

    [​IMG]

    This Cogent shock is a premium unit. The shock uses a stiffer spring to obtain the proper sag numbers for my 225 lb weight. For damping, this shock has a remote reservoir with high and low speed compression adjustments, and adjustable rebound near the lower clevis. Rick made the shock with a 46mm body and a 16mm shaft (stock is 40mm and 14mm, respectively). This allows for a greater volume of fluid, therefore providing performance consistency and more accurate adjustability. The shock body and reservoir are both aluminum, which further aids in heat dissipation (the stock shock is steel, and is an emulsion type, with no piston to separate the fluid from the nitrogen).

    Custom Cogent Shock Vs Stock Shock with aftermarket spring
    [​IMG]

    Why I Did This
    There are 2 major short comings of the DL650 when it comes to rough road/ offroad capabilities: limited ground clearance and limited suspension travel. I want to be able to ride this bike on basically any non-maintained dirt road and not have to worry about getting high-centered. I also want a plusher ride, but with bottoming resistance.

    Stock DL650 High-Centered on a trail ride last year
    [​IMG]

    I know the DL is not a dirtbike and I’m not trying to make it into one. I have a couple other bikes for real trail riding. I’m simply trying to improve it to the capabilities of the other adventure bikes out there, such as the Super Tenere, the GS1200, or the new Tiger 800. I know my modified bike’s offroad capabilities fall short of the benchmarks: the KTM 950/990 Adventure and the F800GS. However, those bikes have some reliability issues and price tags that I’m not willing to deal with, and I probably don’t need that much offroad ability for what I do with my Strom. FWIW, I used to own a 950 Adventure.

    If you just ride on pavement most of the time, 5-6 inches of travel is all you really need, as it keeps the center of gravity low and minimizes chassis pitch during acceleration and braking, while absorbing most small bumps. Now start taking that bike on beat up roads and the forks/shock will quickly blow through the stroke and bottom out if you weigh over 160 lbs. If you’ve ever bottomed the suspension, you know it is neither pleasant nor safe. Even if you don’t bottom all the way, the last 20mm of travel are rather “firm”, since there is an oil lock piece in the bottom of the fork tube that quickly increases the resistance to travel. It’s like pulling your parachute in a free fall (it’s better than hitting a wall). I’ve bottomed out the stock suspension (preload maxed out) on just beat-up “maintained” roads and potholes, using all 135mm of compression travel.

    So the typical thing to do is install stiffer springs (30% higher rate than stock in my case) and heavier fork oil, and maybe emulators (I did all the above). Now the suspension is less likely to bottom out, which is good. Those same roads that used 135mm of compression travel, now only use 120mm of travel and we are almost out of the dreaded oil lock territory. However, we now have to deal with less compliance (i.e., plushness) over all the smaller impacts. Simply put, the suspension now moves less and the chassis moves more. Not a great compromise for comfort or traction, but better than stock in most people’s opinions (mine included).

    With the 40mm increase in travel, I was able to lower the spring rate by 10-20% because there is more travel in the suspension before it will bottom out. Yes, it will still eventually bottom out, but all the impacts up until bottoming cause less chassis movement and better tire contact with the surface, resulting in better comfort and traction. Those same roads that used 135mm of travel with the stock springs and 120mm with the stiffer setup, now use 130mm of travel (the spring rate is 10% stiffer than stock in my case). Another big difference compared to the stock suspension is my bike stays out of the oil lock territory longer, so even the bigger impacts are nicely absorbed by the suspension (no parachute effect).
    #1
  2. OhioPT

    OhioPT Adventure Wannabe

    Joined:
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    Oddometer:
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    Location:
    Columbiana County, OH
    Why not raise it even higher?

    Center of gravity: let’s face it, raising the bike any amount will raise the COG. Consider the Law of Diminishing Returns: a bike that is too top heavy is going to be difficult to handle when the going gets tough, and will offset the benefits of increased ground clearance and suspension travel. About one inch taller than stock is a great compromise, IMO.
    Control: Being able to flatfoot a street bike is important to me for safety reasons, such as controlling the bike at a stoplight. It also provides confidence when trying to maneuver a 500lb bike on less than perfect surfaces. I can comfortably flatfoot my Strom with these suspension changes AND my taller seat. I would not recommend these modifications if you have trouble flat-footing your Strom with the stock suspension and seat.


    Fork tube overlap:
    using a longer damper rod decreases the overlap between the upper (inner) and lower (outer) fork tubes. There comes a point where this will be detrimental to the strength of the forks. With the 40mm longer damper rods, the overlap only decreases about 15% once the additional rider sag is dialed in. This seems reasonable to me. Those who have done the DR/DL fork mods (which uses a damper rod about 40mm longer) have had no complaints about fork strength.

    Limits of the rear suspension: you have to raise the rear of the bike by an equal amount to how much you raise the front, in order to retain its handling characteristics. Raising the rear too much will make the chain ride on the front swingarm guide, increasing its wear. Folks who have raised the rear more than 1.5” have reported this problem.
    Brake line length: at some point the front end raise will require longer brake lines. This is not an issue with my setup, even with my modest bar risers, but my bike doesn’t have ABS.

    Things to be aware of:
    The side stand is too short with these modifications and will cause the bike to lean way over (it’s already a bit short with stock suspension). I cut the side stand and welded in a 45mm long section of 5/8” diameter solid rod. The lift from this was about equivalent to using a 1.25” thick object under the stand (the stand is at an angle, so a 45mm increase in stand length is not the same as using a 45mm thick object under the stand). I still wanted the bike a little more upright so I carved out a ¾” thick block of wood and attached it to the stand foot with a couple screws. The nice thing about this setup is I won’t have to cut and reweld the stand if I decide to lower the bike back down to stock height: easily removing the wood block should allow the modified stand to work.

    Modified Sidestand
    [​IMG]

    The center stand is too short. You can use a 3/4” thick piece of wood under the center stand feet to get the rear wheel off the ground, or weld in extensions for a permanent solution. Or, remove the stand and sell it like I did. Some skid plates allow you to use them to jack up the bike. This is the easiest way to work on the forks anyways.
    #2
  3. SlipChip

    SlipChip Adventure Commuter

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    East of CleveOh
    Nice work PT! :thumb
    #3
  4. sailah

    sailah Lampin' it

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    Haha Mark I read the title and thought our last meeting convinced you to stuff a gsxr 750 motor in your bike....

    Looks good. We'll get in a ride soon when I finish my bike
    #4
  5. OhioPT

    OhioPT Adventure Wannabe

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    Thanks! Hope to catch a ride with you guys soon.
    #5
  6. bumper1871

    bumper1871 Been here awhile

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    Montreal Qc
    Great project. :clap
    #6
  7. Jud

    Jud Long timer

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    Nice work and a great write up.:1drink
    #7
  8. OhioPT

    OhioPT Adventure Wannabe

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    Thanks Jud, you definately inspired me with your DR/DL fork conversion.
    #8
  9. tileman

    tileman Long timer

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    Melbourne, OZ
    great write up. cheers !!!! :clap
    #9
  10. tileman

    tileman Long timer

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    Who exactly did you speak to at Cogent as I think I am going to order the exactly same shock that you did. Shipping is kinda not relevant as I'm on the other side of the world anyhow. :D
    #10
  11. OhioPT

    OhioPT Adventure Wannabe

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    They are a "mom and pop" operation so it's really just Joyce and Rick. Ask to speak to Rick. Everything should be fresh in his head since he just built my shock a week ago. Ask him what spring rate he recommends for your weight. I went with a 600 lb/inch spring, which is perfect for my 225 lb weight. I set it with a tad more preload (12mm from free length) so I was on the lower end of recommended sag- 56mm, which is 30% of the 190mm total wheel travel. That way I don't have to adjust the preload when I add some gear for a camping trip, etc. If I ride 2-up I will add 6-8mm more preload. I also ordered an $8 Ohlins spanner wrench to turn the preload collars.

    You don't want to go too stiff on the spring rate. The shock spring has to have at least 8mm of preload on it for it to perform properly. If you go too stiff you might find that you can only preload the shock like 4mm to keep the rider sag in the recommend 30-33% range for riding solo. That would not be good.
    #11
  12. tileman

    tileman Long timer

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    Thanks. :D
    #12
  13. NADZ

    NADZ Adventurer

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    Feb 27, 2009
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    Sweaty Brisvegas <Brisbane QLD Australia>
    Looking good!

    Do you know what the overall length of the shock is without the "shortening spacer" installed? Im looking at mine and I think I want about a 360mm overall length.
    #13
  14. OhioPT

    OhioPT Adventure Wannabe

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    Rick told me he made the shaft "a few millimeters longer" so I would guess it could be as long as 358-360mm with the spacer removed. He can make it as long as you want (well, up to a point anyways). 360mm would be more than plenty to play with. Like I mentioned earlier, any taller and you will likely run into issues with clearance (between the chain and swingarm, and also between the lower shock clevis and the swingarm).
    #14
  15. Weekend_warrior

    Weekend_warrior Been here awhile

    Joined:
    Feb 18, 2006
    Oddometer:
    539
    I Bought a replacement shock from Rick a few years back on my V-strom. Works great. They are good folks and do a hell ofa job.

    Mine does not have a remote resevore on it though on it. Yours looks a bit more adjustable. The preload on mine is still easy to adjust. I believe it has rebound, but compression is internally valved. The setup is great on the rear of the bike. I didn't want to mess with the ride height on mine, but it works well for what I use it for. I have been to lazy to tweek with the forks much more. They are a bit on the stiff side now, but atleast there is no dive.....
    #15
  16. OhioPT

    OhioPT Adventure Wannabe

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    Rick does an excellent job setting the shock up based on your riding style, weight, experience, etc. I know he played with the valving on mine quiet a bit while on his dyno before shipping it out. I have to say that I really haven't had to play with the clickers yet, so I think he did a great job. The only area that needs improvement is the high speed compression, as I've found that highway expansion joints are just a little harsh. Fortunately, my shock has this adjustment so I'm pretty sure I can tune that out.

    I'm extremely pleased with how well my WeeStrom suspension is performing. Last weekend I was on a group ride with several KTM Adventures and a DRZ400s (all experienced offroad riders/racers). The leader took us to a gravel pit play area with a bunch of open quad trails. I had no trouble keeping up with the spirited pace. I launched the Strom up several small table tops and the landings were remarkable- very plush. I was honestly expecting it to be a little rough, but it felt I was riding a true enduro bike. I have yet to hit the skidplate on anything, something that was annoyingly routine before raising the suspension. My next big ride will be to the Allegheny National Forest trails in PA, so I'm sure the plate will hit a few rocks there, lol.
    #16
  17. junkyardjoe

    junkyardjoe n00b

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    Ohio PT,

    Really like the bike and am building something very similar. I am trying to limit mods but raising the bike as you have done is on the top of the list for the winter. Main question I am interested in is what front spring rate you ended up settling on?

    I only ask since I will be shooting for similar travel and I also weigh 225lbs.

    Also how do you like the on road behavior of the bike since you moved up in travel (brake dive, steering response, etc)?
    Are you happy with this mod? Would you do it again? Anything different?

    Thanks in advance,

    Joe
    #17
  18. Zapp22

    Zapp22 ZAPP - Tejas

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    shameless ad... I have a pair of perfect long front legs if anyone is interested. rode her tall and naked for a season couple years back.

    My experience suffered from comparatives, as at the time she was long-legged I also had just come off a streetized XR650R and was breaking in my now sold '02 DR. rough competition. What I figured out, the hard way, is that even though my inseam is 34" and my arms are long, in really rough terrain, the extra inches of clearance weren't as useful as I had hoped because when you're crawling along, getting a leg down to shove out of a hole or, worse, to backup/out, is quite challenging. here in dry country, its common to put your foot down on what amounts to loose marbles.... roller bearings with hard surface underneath - very tricky to get traction on. when the only traction you can get is with the ball of your foot, its tough to move 500lbs of top-heavy machine like you want to .

    my take is that, tough as the weestrom is, you're better served to pick a REALLY good skid pan, raise the forks as tall as the structure allows, and go.
    oh, and pick a pair of tall tires also.

    handling-wise, I thought the somewhat twitchy low-speed steer was helped a lot by raising that nose into the air. I liked much better the more relaxed fall-in. These days, I run my forks way out there... they are clamped right on the caps
    #18
  19. Dubl-A

    Dubl-A SuckerDucker

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    Interesting project! Keep us updated
    #19
  20. Syscrush

    Syscrush Wannabe adventurer

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    Toronto
    Very cool. I'll just add another endorsement for Cogent - Rick and Joyce are really great, friendly people who are totally into motorcycles and Rick is amazing at setting up suspension stuff.
    #20