Yamaha forks on a BMW F650GS Dakar

Discussion in 'Thumpers' started by skibum_1260, Oct 23, 2008.

  1. farkleface

    farkleface ridin dirty

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    Thanks again for the help. How much for a storage container?? I would be interested in purchasing one. How is the dakar to jump? seems like it would be squirrely on the landing. I already have the ohlins rear so i will be ready to let it fly.
    #21
  2. skibum_1260

    skibum_1260 Been here awhile

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    well its def not a motorcross bike but the yamaha forks def make the front end capable but mine bottoms out in the rear very easily so havent gone to crazy with it yet! and i was asking 110 for them i think, powdercoated black plus shipping.
    #22
  3. johno

    johno Long timer

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    I run 5wt oil in mine on my GSPD. Yammy dealer said standard oil is 2.5wt, and suggested for the weight of my bike, to run 5wt.
    The springs in mine are an unknown. It seems stiff, so am leaving it alone at the moment.
    I run the clickers fairly soft.

    My back shocker is my let down at the moment.:cry
    #23
  4. El Cazador

    El Cazador Mama didnt love me

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    could be a deal breaker for me: will the stock 19" bmw wheel fit on the yz forks?
    #24
  5. drivenbydiscovery

    drivenbydiscovery ´¯`•...¸>`•.¸¸.•

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    ok, i'm going to try this very soon, so i'll let you know :wink:
    #25
  6. WayneC

    WayneC Long timer

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    #26
  7. drivenbydiscovery

    drivenbydiscovery ´¯`•...¸>`•.¸¸.•

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    johno, skibum, a quick question for you guys, (i've been searching various yamaha forums with no luck).

    you both used triple tree / forks from a 2003 or older yamaha yz (46mm lower tube diameter). but would the 2004 - 2008 (48mm lower tube diameter) forks / triple tree also work? is the triple tree different somehow?

    i'll keep searching the net in the meantime. thanks.
    #27
  8. johno

    johno Long timer

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    Not sure on the later 48mm stuff. Its the headstem bearing size you need to worry about. Do what I did, and email someone on Ebay that is selling a set, and get them to measure the bearing shaft size
    on the headstem.
    Not much help otherwise.
    #28
  9. drivenbydiscovery

    drivenbydiscovery ´¯`•...¸>`•.¸¸.•

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    awesome, thanks. offhand, do you know what size the 2003 yam headstem bearing is?
    #29
  10. johno

    johno Long timer

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    The upper shaft section is 28mm, lower 30mm. BMW have 28mm on both.

    The main area of concern when doing a swap like this is bearing
    cup outer diameter. Lucky the Yamaha and BMW have the same size cup outer diameter. So, all you need to do is get a headstem bearing kit for a Yamaha YZ/WR.
    #30
  11. drivenbydiscovery

    drivenbydiscovery ´¯`•...¸>`•.¸¸.•

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    thanks for that.

    looking into it some more, i think the 2004+ Yamaha YZ bikes use the same bearings as the 2003 and older, so theoretically they should work. i actually stopped by a Yamaha dealer today but after posing this question, all i got was dumbfounded looks. so no help there.

    only one way to find out i guess; buy a newer YZ triple tree with bearings and try to graft it on.

    as one of my good mates always says; it's all just a matter of trial and error. with a little more error than trial.

    :D
    #31
  12. johno

    johno Long timer

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    WayneC1, just put a YSS rear shocker on my GSPD.
    Will roadtest, and set it up 2morro.:D
    #32
  13. mtothef

    mtothef Been here awhile

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    when it comes to looking for bearing retrofits, the outer diameter and profile height of the bearings is what matters. if you go to pivot works website and search for the bearing application for your bmw. there should also be a specification for it somewhere, either listing the components of the kit including the bearing dimensions, or the bearing dimensions themselves.

    now, go check for the same for whatever forks you are searching. if the profile height and outer diameters (both upper AND lower) match, then you are in bidness!

    in some instances, the same bearing kit will work for several different forks ('frinstance, the xt600 i am restoring uses the exact kit that early 90s kx500s do, so that ended up being the front end i bought), so it's always a good idea to cross reference the kit number for your bike and see what else it is used in.

    dealers are useless for this kind of info, because it involves a lot of back and forth cross referencing and may not always be absolutely clear. but with some digging on that one website, you should be able to figure this all out. good luck!

    #33
  14. Brute

    Brute Melbourne , outer east .

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    What about the steering lock & ignition key setup . Did you use the same key setup ?If so how did you mount it ?
    #34
  15. Salt fever

    Salt fever this is gonna hurt

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    [​IMG] I kept the BMW post and had the bottom machined to suit the alloy triple from the 08 Husqvuarna as the post is welded into the factory steel ones. This way I also kept the BMW dual locking set up on the headstem. I run aftermarket risers for fat bars. I had to take off some of the metal either side of the plate with the holes in it for the steering lock as the bolts for the new handlebar mounts were hitting it ( not a very good steering stopper as it moves the bars heaps). I run an new Husky front guard and as its one piece it will be far more up to my standards of get offs ( I turned pro in get offs moons ago)≥ I had to run 3 washers between guard and triple at the back two mounts to give the correct angle on it to clear the frame spine and radiator shrouds.

    I have yet to sort out front wheel/brake set up. I have a wheel from a new Aprilia which use the same forks and axle set up, however if I can machine up some spacers and end plugs (threaded one end) I can use the original wheel and rotor, or alternatly find new bearings for the hub to fit the husky/aprilia axle.

    I too am having trouble trying to work out what to do with the ignition block. I will keep you posted as I am a resouceful bastard.


    [​IMG]
    #35
  16. WayneC

    WayneC Long timer

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    Looking quite a mean beast there

    Johno, Will be interested to hear how the YSS shock goes
    #36
  17. Brute

    Brute Melbourne , outer east .

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    Thanks there salt fever . If all goes well I`ll probably have a set of forks & clamps off an 06 yz 450 very soon. I haven`t pulled my Dakar apart as yet but I was thinking maybe the only way to mount the ignition lock would be to cut the alloy mount off the old triple clamp & tig it onto the new top triple clamp & do away with the steering lock .
    #37
  18. johno

    johno Long timer

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    Just done a 450klm ride to Adelaide, and very happy with the YSS shock.
    Will play a bit with it on the way home tommorrow.

    Might have to change to a lighter oil in my forks. Running 5w at the moment. Standard Yammy is 2.5w. I dont have a lot of static sag with my YZ450 forks. Could have been set up firm by PO for serious MX.
    Works better on rough stuff than smaller bumps.
    Will give me something to play with:lol3
    #38
  19. JDRadman

    JDRadman Moto Head

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    I am contemplating the same mod with the YZ forks on my Dakar.

    I am curious about spring rates on your bike. Ski... said he thought his were a .52. Yama OEM or stock for KYB 48Us come with .46 or .44 for 450 and 250F respectively per Racetech (same on the 46U). The stock GS is .62 and Racetech thinks I need a .86 on the GS (160lbs no gear) but they don't make them. I am currently running the TT upgraded springs but don't know there rating.

    So what's the story on race and static sag on the GS Dakar with the standard Yamie springs. I don't understand how a spring sooooo much softer than the stock BMW spring could be too stiff with too little sag? Damping would bleed down under the weight so what am i missing :confused
    Please help me understand this.

    Great thread and I am looking forward to the upgrade...:clap

    Rad
    #39
  20. floridasroadkill

    floridasroadkill Adventurer

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    Same bearrings but longer bearing stem.Huge improvment with longer rear shocks.YZ 400 from 1999.
    [​IMG]
    #40