Keep it in the family, DRZ250 Cartridge forks onto a DR650

Discussion in 'Thumpers' started by Eddieb, Nov 17, 2012.

  1. Rob.G

    Rob.G Mostly Harmless

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    Potentially stupid question, but is there a big enough difference between the DRZ250 forks and DR650 forks with Gold Valves and springs installed?

    Rob
    #21
  2. tntmo

    tntmo Been here awhile

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    Are the modded DR650 forks adjustable for compression and rebound damping? The DRZ250 forks are.
    #22
  3. Gryphon12

    Gryphon12 Long timer

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    Ok, based on the reply I received above, stock DR-650 forks are damper-rod forks with progressively wound springs.

    Racetech "Gold" valves are upgrades to a cartridge fork suspension. You can't add Gold Valves to a damper-rod fork. You add Gold Valve Emulators - but they are still damper rod forks. Based on my understanding, emulators and intiminators (sp?) have slightly different characteristics, but either (both) take the damper-rod applications about as far as they can go.

    Based on my understanding (and marketing / sales pitches aside), cartridge forks are generally better than damper-rod forks (but not always - on some less expensive street bikes, for example) - and Gold Valves are usually an upgrade unless your stock forks are very high-end.

    So, in general, the progression goes: stock damper-rods, damper-rods with emulators, stock cartridges, cartridges with after-market (e.g. Racetech "Gold") valves.

    There will be some overlap, and grey areas, depending on what you are starting with. Going from the stock DR-650 damper-rod forks to a DRZ-250 cartridge fork, sprung for your weight and valved for your application, is a big two steps up, based on my understanding to date. Suspension dynamics is a very complex subject, and while I'm an engineer, I'm no expert. Hence, I'm always willing to learn. If any of the above sounds flat-out wrong to those of you who know suspensions, please chime in and educate all of us!
    #23
  4. eakins

    eakins Butler Maps

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    as in undo. an air gun spins the bolt out faster than can the fork innards spin.
    yes if you put the spring & cap back in that might enough friction to all hold the cartridge in place.
    #24
  5. eakins

    eakins Butler Maps

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    maybe not but you're thinking of emulators on the DR forks (or intiminators)
    the DRZ advantage is there are external adjusters.
    #25
  6. bkoz

    bkoz Been here awhile

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    The Gold Valve only works on the compression dampening on the DR650 forks. If you want to change the rebound dampening you have to change fork oil weight or drill out and/or weld closed the rebound hole in the damper rod.

    DRZ250 forks allow for externally adjustable rebound and compression and the ability to shuffle shims to change the dampening, rebound and compression.

    Makes me wonder...............Could the DRZ250 cartridges be installed into the DR650 forks???????? Ebay here i come.
    #26
  7. Eddieb

    Eddieb Long timer

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    So I popped into my local dealer tonight and they copied the exploded diagram for the DRZ250 forks out of their documentation.

    Interestingly they don't show any sort of adjustable shim stacks and according to their book the diagram shows everything in the forks, nothing comes apart any further than is shown.

    I also asked them to find out the price of part 16, as the adjuster screw is stuck in both my fork legs and I may not be able to get them unstuck. There was no price on file as that part has never been imported here individually by Suzuki NZ.

    Sorry for the crap pic, I don't have a scanner.
    [​IMG]
    #27
  8. Gryphon12

    Gryphon12 Long timer

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    Aren't shim stacks for Cartridge forks? DR650's are damper-rod forks. That's the whole point of this thread. You don't fit cartridges inside; you replace them with cartridge forks from the DRZ-250. Or am I missing something?
    #28
  9. Eddieb

    Eddieb Long timer

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    I'm doing a full replacement, removing the DR650 forks and fitting DRZ250 forks. The pic above supplied by my dealer of the DRZ250 internals doesn't show what I expected to see in terms of shim stacks.
    #29
  10. colyrider

    colyrider n00b

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    Hello Eddieb. I did this mod to my DR650 about 18 months ago and although it is good I am not sure I would bother again.

    I used a supermotard disk kit that allowed me to use the 250 wheel and a 320mm disk and caliper reloating bracket. There are issues with the "floating disk button" circlips not being suitable for highway use and I overcame this by making cupped aluminium washers and countersunk screws to guarantee that the circlips could not come loose.

    The other thing I did (that may not have been necessary) was to machine the mudguard lugs off the bottom of the triple clamp and redrill and tap the mudguard mounting holes so the guard is 15mm higher than standard. I did this because the 250 forks have 20mm more travel than the 650 forks and I did not want the tyre to jam under the guard on full compression when using a full knobby tyre. It was not very difficult to mount the steering stem in my lathe and do the machining so I did it just to be sure.
    Happy to compare notes on what you did and how well it works. I had my forks resprung and revalved to suit and it definitley is better than stock forks but now that I have done it I would recommend people just use gold valves, 10 weight oil and correct weight springs to suit their riding. I did 7000 kilometres with well set up standard forks like this before doing the 250 fork mod so I have a good comparison.
    :D
    #30
  11. warewolf

    warewolf Tyre critic

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    Tom Jones moment... "It's not unusual". :evil It's just that they don't expect you to service - and don't sell separately - the shim stacks so there's no exploded diagram.

    Anyway... typically on USD forks, part #15 is the compression (funnily enough, aka base) valve complete assembly including shims and adjustment needle. Is your adjuster needle stuck in the assembly? Might be worth taking the base valves to a suspension guru, they might be able to fix it.

    The rebound valve (aka mid-valve) assembly is trickier to spot on that diagram for RWU forks, but I would guess it is part #30. On compression its pushed into the oil-filled cartridge, and then on rebound it acts like a screen door closer. :lol3

    Or have you not got the cartridges out yet? The shim stacks should be pretty obvious once you have them in your hand. Again, a suspension guru most likely can fix it, unless they are really, really poked.
    #31
  12. bkoz

    bkoz Been here awhile

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    Yes that is the point of the thread. But I was throwing the idea around of removing the damper rods from the DR650 and installing the DRZ250 cartridges vs changing the whole fork assembly and having to play with brake fitment. Just thinking out loud in cyberspace.
    #32
  13. bkoz

    bkoz Been here awhile

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    See Warewolf's post.

    He is absolutely correct about the manufacture not showing more info on the forks. They don't want you going inside them. The same goes for shocks.

    As far as your seized adjusters it is best to strip the forks down. It will be much easier to make any repairs. The adjuster bolt itself is very soft, beware.

    Take as good look on the interwebz for a video or disassembly pics. Maybe even snoop around some Honda XR forums, I believe the XR400/XR250 forks are very similar, if not identical.
    #33
  14. Eddieb

    Eddieb Long timer

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    I've been looking for disassembly pics or video for these for a while and either I'm not using the right search terms or there's nothing out there. I could find lots on other cartridge forks, mostly USD's but nothing for these.

    After everyone's assistance I had a closer look at things today.

    The lower bolt and adjuster
    [​IMG]

    The adjuster is seized
    [​IMG]

    That looks like the base of a shim stack in there
    [​IMG]

    The shim stack looks like it's pressed in with an o-ring to seal things
    [​IMG]
    #34
  15. Eddieb

    Eddieb Long timer

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    At this stage I am not going to alter the valving as I don't know how it will behave as it is. I'm planning on getting the adjusters working then refilling the forks to factory spec and seeing how they perform over a month or 2 and what different adjustments do. After that I will decide if I want/need to update the valving.
    #35
  16. warewolf

    warewolf Tyre critic

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    Good plan.

    I've never seen anything quite like that setup, but then I'm not that experienced. I never touched my DR-Z250 forks apart from the odd minor clicker adjustment, 'cos I paid a suspension guy to service them. All he did was add a little more oil to stiffen the latter part of the stroke, which he did a couple of times over successive services. He used to watch me ride at club events etc when he caught up to me, and tweaked from there.
    #36
  17. kiwipeet

    kiwipeet Uber Cyber Loafer

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    Very cool. Saw link on fb.. hope I can find my way back here for a nosey tommorrow :)

    Sent from my HTC One V using Tapatalk 2
    #37
  18. Eddieb

    Eddieb Long timer

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    I had to take my car in for it's WOF (Warrant Of Fitness, 6 monthly mechanical check) this morning so I put the spring and cap back in the fork leg I couldn't get the bottom screw out of and took it down to the garage with me. 1 quick blip on their rattle gun and it undid.

    I'm away for the next 10 days so there won't be any further progress for a little while.
    #38
  19. Eddieb

    Eddieb Long timer

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    I rang my dealer back today and they had received a price from Suzuki NZ for replacement lower bolts with the compression adjuster in them.

    $214NZ each!

    I'm really hoping I can salvage my ones, otherwise it's Ebay time.
    #39
  20. el capitan

    el capitan Adventurer

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    Drown them in a glass of WD40 and let them sit for some days - it is quite likely you will be able to work them loose afterwards. We had a similar problem on a mounted shock of a 91-Ducati 900 SS. It was solidly stuck in the beginning, but could be loosened and normally adjusted afterwards. No problem since.
    #40