Hey Creeper - New BST

Discussion in 'Thumpers' started by accadacca, Feb 7, 2005.

  1. accadacca

    accadacca Hard Rocker

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    Hey Creeper,

    I know that you are still running the BST 40. I decided to put this post on ADVrider instead of the other forum, because there are probably more over here that are running it. Anyhow I have read quite a bit on the carb but I am just beginning to get my feet wet. I have a 96 620 RXC. Right now it has a Dellorto. Which has worked pretty good, except it coughs at low revs and when the bike gets hot it likes to stall at low revs.

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    I bought a brand new BST with throttle, cables, etc. It came off of a 03 625 SXC unused. My Dad is running this same carb on his 625. He had some initial problems with it. Then he went to the local KTM shop to buy an extended fuel mixture screw. They gave him a Zip Ty Racing FMS-01 screw. (http://ziptyracing.com/display/eCommerce/Products.asp?CategoryID=110&order=) Which is made for the FCR. However it fits and works really well for the BST. Some have complained about its venerability, because it protrudes below the bottom of the carb. Well the idle screw does the same thing and is the same distance.

    <o:p></o:p>
    Anyway I am thinking of buying this same screw. When my Dad bought this screw and adjusted it, he has been really happy with the bike. Although I think he is probably running a little bit on the lean side. Well before I ramble any longer I am looking for some settings from someone who is using this carb. The carb is coming to me untouched and with the stock jets. It is supposed to come today. I live at 4500ft and ride up to 10,000ft. I am running the stock UGS Supertrapp exhaust.

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    Thanks in advance for any input,

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    Accadacca

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    BTW…..I used you “how to” on adjusting valves for my bike. It was my first time and thanks to your write up, it was pretty easy. It will be much quicker next time. My Dad and I rode on Saturday with near 50-degree temps. Ride report http://uutah.com/forum/viewtopic.php?t=225. Now today 4 inches of snow on the driveway and it was snow blower time this morning.
    #1
  2. creeper

    creeper Still alive...

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    Wow! big font time! :lol3

    Anyway, if it came off a '03 SXC it prolly has a 152.5 MJ, needle clip on the #3 groove, a 45 pilot and 1.2 air (someone correct me if I'm wrong on this).

    Assuming your running a aftermarket muffler or opended up stocker, and assuming you have an opened up air box... lots of assumptions here... and taking into account your elevation requirements... and this is all an semi-educated guess on my part. :lol3

    I'd drop the main to a 145 - 147.5, leave the pilots, drill the slide transfer ports to .110" - .125" or 3mm, move the needle clip to the 4th position from the top and adjust low speed mixture and idle for best effect.

    You may end up going up or down a size on the main, and you may end up putting the needle clip back to the #3 position, but everything else should be pretty close.

    Good luck with that and thanks for the tip on the Zip Ty extended screw. :thumb

    Creep
    #2
  3. ChrisC

    ChrisC Amal sex?

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    Hey Acca,

    Did you compare the metering tips on the OEM screw and the Zip-Ty?

    Seems like we would of heard of this a long time ago....

    [​IMG]

    Sounds too good to be true to us BST! Cultists. :lol3

    CC
    #3
  4. accadacca

    accadacca Hard Rocker

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    Whoops...Fixed! No! I am not blind! Insert joke HERE :D

    I am running a standard ST OEM pipe. It has bout 7 discs. I may be getting a Remus silencer soon. Current pipe looks like this:

    [​IMG]

    And my air box is a bit different then the newer LC4 models. It is tucked under the seat and has a cover on top with gel battery. So I cant really make a side cover with holes like others. Could drill some holes? Looks like this:

    [​IMG]

    Thanks to the guy parting out a '95 on ebay for the pictures. Thanks to creeper for the setttings. I will pick up a few jets to try.

    Drill the slide? A little lost here....once I see the carb I may get it. Part #?



    My Dad was the first to try this screw on his 625. When I get my carb today I will take a picture of both and then post. I need to run down to the shop and pick up this screw. Does look the same looking at the parts diagram? #17 right?

    [​IMG]
    #4
  5. ChrisC

    ChrisC Amal sex?

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    Muchisimas gracias... :grinner

    CC
    #5
  6. ncfitton

    ncfitton Summit Adventurer

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    I have the same airbox as you. Mine came with the top cover cut in half, Dellorto carb, and a custom made exhaust. All these mods were done by Jimmy Lewis on this site and the bike runs well.

    Good luck with the BST.
    #6
  7. creeper

    creeper Still alive...

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    You'll see the two holes on either side of the needle hole in the slide/vacuum piston when you remove it.
    #7
  8. accadacca

    accadacca Hard Rocker

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    The Old stock fuel mixture screw & a new Zip Ty Racing extended screw. The tips are not exact. However as the screw raises and lowers it is essentially doing the same thing.

    [​IMG]

    Here is a picture of the screw on the carb.

    [​IMG]
    #8
  9. creeper

    creeper Still alive...

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    Time to order a Zip Ty screw... eh Chris? :lol3

    Thank your dad for being the guinea pig on this item... the word will go out from here. :nod
    #9
  10. ChrisC

    ChrisC Amal sex?

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    Zip-Ty...fuck yea!


    CC
    #10
  11. Drif10

    Drif10 Accredited Jackass

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    OMFG. I just got a chub from looking at that. WhyTF don't all carbs come with this?

    Daddy's goan git'im one. :evil
    #11
  12. meat popsicle

    meat popsicle Ignostic

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    So much for that $30 motion pro idle screw fancy-schmancy screwdriver I bought :arg

    :lol3
    #12
  13. Velocibiker

    Velocibiker Adventure Antagonist

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    I'm going to wait for the actual ride review before I jump in. Sounds "too good to be true" and that always makes me leery. :patch
    #13
  14. creeper

    creeper Still alive...

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    Got one comin'. :D
    #14
  15. Surly

    Surly surly adventurer

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    just where is this 640 valve adjustment thread/doc?
    me...likie...readie
    #15
  16. accadacca

    accadacca Hard Rocker

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    My Dad has been riding his with this screw since last summer. For him it was just what the doctor ordered. And he is more particular than most. The problem with the DAMN stock screw is the access.

    Tracked it down for ya. http://ktmtalk.com/index.php?showtopic=77948&hl=lc4

    It sure helped me out, as a first timer. Thanks again Creep. :thumb
    #16
  17. dagwood

    dagwood Banned

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    Sweeettt... That screws a bitch to get to deffinetly yea deffinetly.
    :thumb
    How much $$ for the zyp-ty screw?
    #17
  18. SoilSampleDave

    SoilSampleDave Dr. Zaius was right!

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    Creeper - Whyfore you no like FCR and worship BST:pope ???? Having had a BST on an XR400, I thought it sucked. I don't plan on hammering whoops on the ADV (although it might happen), so I'm not in any great hurry to replace it, but there are quite a few fans of the FCR out there.

    BTW, the valve adjustment article is excellent.
    #18
  19. Surly

    Surly surly adventurer

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    #19
  20. creeper

    creeper Still alive...

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    I've ridden FCR 39 and 41 equipped LC4s, and although they have a bit more snap when you crack the throttle, they are not as smooth at a steady throttle and above half throttle don't seem to offer any additional gains. I rarely ride at readline... so there may be a decent gain there as well. This is all seat of the pants of course.

    I do have an interest in the Mikuni TMR41 that Husqvarna used last year, mostly because I'd like to see if I can get one to work... something Husky couldn't seem to do, and the reason they switched to the tried and true FCR in '05.

    Thanks... I get by with a little help from my friends.
    #20