The BST-40 Bible

Discussion in 'Thumpers' started by laramie LC4, May 31, 2008.

  1. Loadedagain

    Loadedagain making chips

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    i love you guys :clap
    #21
  2. ChrisC

    ChrisC Amal sex?

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    :killen
    #22
  3. NordieBoy

    NordieBoy Armature speller

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    In the DR manual it's 14.7mm +/- 1mm.
    Just wondering how close to parallel that is?

    Attached Files:

    #23
  4. 1stworks

    1stworks dude

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    Great post!!!!

    :clap :clap :clap :clap :clap :clap

    firstworks
    #24
  5. postaldave

    postaldave gone postal

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    ktm noob here.

    i just came across this post and thought i would bump it to the top.
    if anyone wants to make a howto post this is how it is done.

    great job!
    #25
  6. laramie LC4

    laramie LC4 crash test dummy!

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    it sure looks parallel to me. i would imagine that even thought the carb is in different bikes that the float heigth would be the same. the manufacturers just choose to use a different way to measure the setting.



    thanks :thumb

    laramie :beer
    #26
  7. meat popsicle

    meat popsicle Ignostic

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    Hey laramie,

    (the reason I was going thru all your thumper threads was to get to this one)

    I wish I had a printout of this on a ride this weekend. I crossed the state so that I could pull my carb and unstick the float... :bluduh

    It all seemed to go OK, 'cept I didn't pay any attention to a float weight... things seem fine so maybe I got lucky and it hung on! Oh, and I installed the enricher slide valve assembly backwards (spring first, then slide valve! :doh). I didn't notice that in your Bible - do you recommend not servicing it?
    #27
  8. laramie LC4

    laramie LC4 crash test dummy!

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    you can pull the enricher but i hardley ever do. its usually never dirty and dosnt need adjustment. you certianly can pull it though and check. another thing that i didnt know about, was the fuel screen in the fuel nozzle. i had someone over at ktmtalk show me it. i never knew it was there.

    laters,

    laramie :beer
    #28
  9. KTM640Dakar

    KTM640Dakar Motorsick

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    This guide should be the first carb sticky in the index thread.

    Great stuff.
    #29
  10. meat popsicle

    meat popsicle Ignostic

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    I'll have to read back thru your guide and look for the fuel screen/fuel nozzle assy.

    Oh yeah, I reassembled the enricher (aka choke) and thought I might share a thought or two and some pics. First off, if you are going to disassemble and then reassemble this you will want to do it with the carb off the bike, or at least with the throttle assembly out of the way. With things like this:

    [​IMG]

    it was a pain in the buttocks. I found a way to get it reassembled but that was only after quite a few search and retrieve missions for the slide valve and/or spring after they jettisoned into the bowels of the engine... so what I did with these parts:

    [​IMG]

    was WRONG :rofl (see GK's post below, so the remainder is edited after looking at the parts fische). So you should slide the spring over the cable end and then connect the slide valve onto the cable, maybe pull the lever on the handlebars to help hold them together, but they should stay together OK this way. Then you can try (and try, try again... ) to push the assembly into the carb and tighten the cover/nut to secure it. I ended up using needle nose pliers to reach the nut, and was damn sure not to give it too much torque because it's only plastic.

    Mine was clean and beautiful after over 10K miles so I guess you are right Laramie; might not be a necessary chore. I did it originally instead of disconnecting the cable from the lever.
    #30
  11. G.Kennedy

    G.Kennedy ...

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    Ya might want to check that .... if I am reading your description correctly ... you have the parts backwards.

    Pretty sure the spring goes between the brass part and the threaded part. Spring goes on the cable first then the brass part .... the tension of the spring holds the brass part in place while installing .... take a look at the microfiche

    .... Pretty sure.
    #31
  12. meat popsicle

    meat popsicle Ignostic

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    yeah you right GK... why didn't I think to look at the fische? :lol3 well, at least the tank ain't back on yet. I'll go back and edit my post. OK, third time will be the charm.
    #32
  13. BurnieM

    BurnieM Nipple boy

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    I guess most people know that the DR650 also uses the BST40 carb

    Mine had phillips screws holding the bowl on.
    They were a bastard to get off. I ended up liberally soaking them in WD40 before leaving them to sit for 20 minutes.
    One head was mangled getting them out. Replaced with 2 allen head screws.

    Kientech have a range of DR parts including a fuel screw which should fit all BST40
    .
    #33
  14. bmwktmbill

    bmwktmbill Traveler

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    Burn,
    If you get that stuck Philips screw, mangled head syndrome again, take a small needle nosed vice grips and lock on to the head of the screw...it will come loose easily. I carry a small needle nosed vice grips at all times.
    Handy in many ways.
    b.
    #34
  15. RightSpin

    RightSpin Been here awhile

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    Laramie, consider yourself with groupie. That walkthrough just saved me a ton of time. I really appreciate it.:thumb
    #35
  16. Gregarious

    Gregarious Been here awhile

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    Great thread -- I've been using it help diagnose a leak problem. This should definitely be on the LC4 Index.

    One item I would add is the air jet:
    http://rides.webshots.com/photo/1058341970036995609fbyxiT

    I didn't know what these were until other threads discussed 1.1 and 1.2 air jets.
    #36
  17. 1stworks

    1stworks dude

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    Thanks for the post!!!


    firstworks
    #37
  18. meat popsicle

    meat popsicle Ignostic

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    Can't remember where I saw folks discussing fitting throttle cables to a carb and MacGuyvering the old 90 degree cable adjuster assembly onto the new cable, maybe because they didn't know about this:

    http://www.sudco.com/100degree.html
    #38
  19. voidjava

    voidjava n00b warrior

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    how i can install this? i am trying but is too hard
    [​IMG]
    #39
  20. NordieBoy

    NordieBoy Armature speller

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    A bit of wd-40 or 2 stroke oil smeared on the o-ring.
    #40