DR650 Shock Rebuild

Discussion in 'Thumpers' started by P-nut, Jan 14, 2008.

  1. eyedragaknee

    eyedragaknee McGuyver

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    In Cary.

    175 lbs 2007 DR
    On the gas coming into an uphill washboard road, the thing just plain sucks and feels like it will rip the chain off. Have to get off of it to keep the bike from coming apart.

    I'm IN
    #61
  2. DRinda505

    DRinda505 I'm right behind you.

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    Actually I do want more rear ride height, I'm 6'4". There isn't much room to shorten the dog bone linkage. The DRZ forks have 11.5" travel vs the DR forks which are 9 or 10" (can't remember). Anyways I like the idea of increasing rear shock travel and hence rear wheel travel. Also like the ride height adjustment by screwing in or out the shock clevis independent of the spring preloading. It's not that I ride my DR like a dirt bike (its too heavy, and I can always go steel my bros 04 KX500), but I like to have the suspension available, even over less demanding terrain or slower speeds a good suspension makes life more fun and safer.

    Put the DRZ forks on yours NC_Rick, it is a big improvement.
    http://www.advrider.com/forums/showthread.php?t=255915
    #62
  3. NC Rick

    NC Rick Cogent Dynamics Inc

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    Yep, it's done. The first shock I built for an actual customer. This one has the Hard Anodize coating and Jessie's 7.6 spring which fits even better than the stock one because the diameter is the same and standard on both ends.
    [​IMG]

    The special adapters that are needed for the stock lowering system, are no longer needed and the spring clip fits snug as a bug.
    [​IMG]

    The hard coat makes the shock feel way smoother working it by hand, I cant wait to ride with it once the rest of the bodies get run and I get my own shock built like this one.

    I have about 8 shocks in this build (we did this one first to help a customer get his bike back on the wheels). Future shocks will likely be in a "group buy" type of deal again. I really cant make money dong these at such low volume (even with the group buy). Several parts are machined by hand and I end up with about 4 hours in each shock, not counting all the work with the anodizing. The anodizing is the big thing and I need the batch size to make it possible at a reasonable cost.

    I never intended these as a real "product" for Cogent, I was doing mine and those for a few good friends but the word got out (I think it was on Maximum Suzuki or Thumper Talk) and people started calling (one of you guys sent me his shock and told me to mod it once I figured it out!). I really love this damn bike and I really like to do this stuff so if I end up with 20 or so DR 650 riders who have them, that will be cool. If it looks like the demand stays there, I will have to do something else on the custom work to make these more producible.

    eyedragaknee, I was out with one of the early iterations of this shock riding with another old timer who hangs out on this forum and this guy can flat ride (he raced enduros for years) I could not get over the fact that he was staying on my but most anywhere on a bike bigger than mine. Well we got to an up hill section that was several miles of twisty and steep up hill with tons of high frequency wash board and I just totally disappeared from him and the rest of of our group. I was doing 50mph on that stuff and could carry almost full power before the rear would controllably slide. I was having a blast power sliding on the stuff. The thing that was holding the bike back was the forks with emulators and springs (with the stock and even the RaceTech moded shock, the fork was still better than the rear.

    DRinda, the fork is a tempting mod but my brain (OK pea-brain) has been mulling over an other option that would be more stealth and that would be to install a set of cartridges into the stock forks.

    With regard to your shock, I would really want to make the rear travel be more inline with what you have in front, that will do a couple things (besides making the bike taller), it will give both ends a similar ability's on big bumps (or jumps) and more importantly allow a softer spring rate for a more plush ride. Matching front and rear suspension performance is something I always strive for.
    #63
  4. darmahman

    darmahman "Illogically Deluded"

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    Man, Rick, does that look nice. That isn't the one I sent you, is it? Even if it isn't I imagine it will look real similar except for the pre- load adjusters!:evil
    Mike
    #64
  5. eakins

    eakins Butler Maps

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    does the shock body have to be coated?
    would not having it, lower cost?

    what about not anodizing the adjuster (red knob) or anything to save cost?
    i don't need a piece of jewerly...mine would be dirty in 2 minutes.
    remember cost is key for most of us.

    what about outsourcing the alum. parts to a cnc guy? guy in my town is in great need of cnc work. his machine sits unused.
    you would be the assymbler/fine tuner.
    #65
  6. meanstrk

    meanstrk broke ass knee dragger

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    I am in Carthage if you want to check mine out when I get the new shock installed. (Mine is one of the 8 he has right now) I would have no problem meeting up so you can see what you think.
    #66
  7. NC Rick

    NC Rick Cogent Dynamics Inc

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    Mike,

    Yours is in with mine and the rest of the batch. The bodies go in for hard coat on Monday. Depending on when they come back, I may have them all together by the end of the week.

    Eakins,

    The Hard Coat anodizing is optional ($45) and is not for looks, it is a performance coating that makes the shock have less internal friction, last longer (like a LOT longer) and also helps keep the oil cleaner. You don't need it. If you were to send in a shock to RaceTech for that coating you would be looking at about $120.

    As far as the other parts, many are shared with other shocks we build. Doing those one off for each shock and these things would cost many times more. I am not too worried about my volume on these (this is no get rich scheme) I am just tying to make the best shock I can for a decent price. This is the answer for me and my bike and if it works for a bunch of others that will make me and them happy! A lower cost option that works very well is the RaceTech Gold Valve, I ran one of those for a couple years. They cost $169 but we discount them. installation from us is $85 (we are a RaceTech center). For the $379 we are offering our upgrade at, you get the rebound adjustability as well as a new seal head assembly that includes the shaft bushing and seals as well as a new shaft. Basically it is a new shock that is of very high quality. I don't want to let anything out of this shop that isn't at least excellent. Providing people keep up with a service every few years ( have us do an oil change and re-charge) I will replace any parts that wear out (the parts that come from cogent) at no cost, forever (same owner). I think it is a great deal.
    #67
  8. eakins

    eakins Butler Maps

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    are you talking about a coating on the shaft? i understand that.
    i was talking about the dark grey coating on the shock body. that seems like bling only, but maybe i'm missing something.
    #68
  9. NordieBoy

    NordieBoy Armature speller

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    Inside the shock body too...
    #69
  10. TheMagicMan

    TheMagicMan Adventurer

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    Time for me to start saving for this thing. It is a must buy for me.
    #70
  11. Eugene

    Eugene -

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    Thanks for all the work Rick. :clap

    I'm interested in your services in some form or another. I do have a question regarding springs and the Racetech option.

    I weigh 160lbs without any gear on and from what you've stated I wouldn't need an aftermarket spring for your shock. How does the stock spring work with the Racetech gold valve kit? Is it more sensitive to springs?

    Also, whether someone chooses to go with your shock or the Racetech route, would I need to calculate my weight by adding in extras like loaded luggage and a larger gas tank?
    #71
  12. NC Rick

    NC Rick Cogent Dynamics Inc

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    Eakins, The dark gray is hard anodizing and has nothing at all to do with looks, aluminum is a soft material and a poor wear surface for the Teflon piston band to run on. What happens is a little higher friction to start, then the aluminum starts to wear and makes fine particulates enter the oil making a more abrasive slurry, causing more wear and so on. The cast aluminum body of these lower priced shocks are the worst offenders. By putting this special coating on the body, there is a 0.002" "skin" that is hard as glass and this is a very good surface with less friction and excellent wear resistance. The oil stays cleaner and the shock lasts better and works better too. the coating makes the body first class for building a new shock on. If the original body is scored or a little worn, we use a special honing process to bring the bore back into a good condition (a little like redoing a cylinder). I am not at all into bling, it's all function :D

    Eugene,

    I generally talk to each of my customers about the shock set up and yes these things are considered. I am about 215 lbs and used the stock spring with the gold valve setup and felt it was excellent. I really think the stronger spring is needed only over the 220 lb mark. Check your sag now, look for the 3.5-4" of sag (about 30% of your travel) and see how much unloaded sag you have. If the unloaded sag is a small value (say 1/4 inch) then your spring is too soft, if on the other hand it is a big value (like 2 inches) your spring is to stiff.

    I did the Gold Valve with the RaceTech recommended settings and it was good but could be a little stiff when it hit the secondary stack (I actually thought it was bottoming before I ran our shock travel data recorder on it. I could not bottom it, even jumping (OK small jumps but jumps). If I were setting up another, I would use a softer secondary compression stack.
    #72
  13. Navaho

    Navaho Long timer

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    Good info. I am finding my RT shock so stiff, I have to adjust the compression to the softest setting. Raceworks in Louisiana did mine but it was his first DR650.
    #73
  14. NC Rick

    NC Rick Cogent Dynamics Inc

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    The RaceTech Valving can be adjusted by changing the internal shims. There is a bleed jet that can be changed too, All that, requires the removal disassembly of the shock. Therein lyes the reasoning for the external adjustment. The compression adjuster on our stock DR 650 shocks is quite limited in what it will do. By totally opening it up the spring tension that controls the blow off is basically gone and you get some more bleed for fluid traveling between the shock body and reservoir when the shock shaft enters the body. A real bleed control in the form of a needle jet with a knob controlling it ant the bottom clevis of the shock is what we have done on our new DR shock conversion, this GREATLY improves the adjustability of the shock. This adjustability is accessible at the side of the road or trail, just by using your fingers.
    #74
  15. Jackazz

    Jackazz Been here awhile

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    OK I'm interested, what do I need to do to buy one? It's a rare snow day in Seattle and I can pull the rear shock today! I would love to be able to hit washboards and whoops with some speed with this bike. I remember the first time I hit some whoops at the same speed I ride them on my dirt bike and I thought I was going to crash hard, the bike started pogosticking and wallowing and I learned my lesson quick.
    "T"
    #75
  16. Dr. Love

    Dr. Love Adventurer

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    Probably nit-picking but doesn't 3.5-4 inches of sag on the DR650 correspond to 34% - 39% of total travel?
    #76
  17. NC Rick

    NC Rick Cogent Dynamics Inc

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    Sorry for being so slow Dr Love. You are correct of course! While the often quoted recommendation is 30-35% of travel (10.2 on our beloved DR 650). There isn't a real hard and fast rule. 100 mm or about 4" is often used on dirt bike rear suspension as a starting point. At the end of the day, rider preference has a lot to do with it. I personally like the bike with a good bit of sag at the rear, it just feels better to me. 4" feels much better than 3" and makes the bike a little lower (I am close to 6'2"so this isn't a BIG deal but I like reaching the ground on those side hills).

    I would love to hear what springs/ vs sag/ vs free sag some of you folks are running.

    Here is a photo of the DR shocks I have (ready for anodizing) from this past Monday:
    [​IMG]
    #77
  18. meanstrk

    meanstrk broke ass knee dragger

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    Sweet! Which one is mine? :clap

    Any estimated completion date on these Rick?
    #78
  19. Eugene

    Eugene -

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    I sent you a PM regarding sag but maybe someone else can answer.

    I'm awaiting an aftermarket tank and a few other bits. Once I get everything, I need to measure my sag to see where I'm at with springs and preload adjustment.

    I'm trying to measure the sag myself. I rigged up a way to measure it using an allen wrench, duct tape, curtain rod, zip ties, and a marker. :dutch

    It would be a little easier to measure the race sag if I could use a rear stand like a pitbull. My question is, will it throw off the measurement? Is this a no no when measuring sag?
    #79
  20. NC Rick

    NC Rick Cogent Dynamics Inc

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    Meanstrk, Yours is next to the second one from the center :evil

    Eugene,

    Sorry I missed your PM I don't get many on here. I happen to be very well prepared to answer that question because I was just doing the same thing myself. You can use a rear stand providing the rear stand supports the swing arm as close to the axle as possible and you also block up the front wheel by the same amount of clearance you end up with the rear wheel being off the ground by. Having the bike on an angle noticeably alters the weight bias and thusly the sag measurement. My friend made himself a paper scale and used a laser pointer to hit it.
    #80