KTM LC4 (640) Thread Index

Discussion in 'Thumpers' started by meat popsicle, Jul 9, 2005.

  1. Marten660

    Marten660 Adventurer

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    Now i know how to upload pics (at last..) i want to show you my LC4 adventure:
    [​IMG][​IMG]
    Uploaded with ImageShack.us
    Is an '05 witch i bought new, but had to respray after a serious accident in '06.
    Fine bike, but sold it a couple of years ago...

    Today i own a different LC4.. (bought in jan. this year en restored en had it sprayed in Galoises colors etc.)
    [​IMG]
    It 's a 660RR and has a lot more power compared with the 640adv!
    And the noise is also a bit (...) more :rofl
  2. bikemoto

    bikemoto Tyre critic

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    Nup, doesn't work as the 640 self-dusts.

    I ran my bike for years and years with the OEM configuration (closed side and snorkel in) and it still dusted up pretty bad. I have not noticed any increase in dusting after opening the side and removing the snorkel.

    Carry several filter skins which can be changed in a couple of minutes. That will get you through a long dusty day (or days) without having to clean the filter itself.
  3. timolgra1

    timolgra1 Been here awhile

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    Thanks for the link, I must have missed that thread when I was searching for info:clap

    I'll give it a try with the side closed back up, snorkel off and may make a screen for the top.....and use filter skins.
  4. bmwktmbill

    bmwktmbill Traveler

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    IMHO, no screen on top as it willl disturb the smooth air flow/ movement-motion into the box and to the filter.


    IMHO.
    bill
  5. beek-02

    beek-02 blazing a trail

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    Bill is correct to an extent. This really depends on the carb you have. If you are still running a stock bst 40 he is absolutely correct. In my experience if you open up the airbox to much you establish no pressure(vacuum) in the airbox. The reason this is bad is because that is the way that your carb operates. It creates a lag until that airflow velocity/pressure is reestablished. With a fcr/pumper carb open the intake and exhaust as much as possible and let that (and off course the motor itself) be your only restriction. As far as filtration goes, there are many theories, but as long as you are keeping the dirt out and the air coming in your, theory is as accurate as any other. Beek

    Sent from my SCH-I535 using Tapatalk 2
  6. timolgra1

    timolgra1 Been here awhile

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    Thanks, I'm using an FCR 41/JD jetting and Akro exhaust.
    I've refitted the blank side cover before reading the above and soon as I get chance will try it out.

    But here's a question regarding JD jetting.:ear
    I've set the bike up as per JD recomendations for sea level except the needle is on the top notch and runs perfect now. (ie. I've had to drop the needle 3 notches)

    So running at altitude, say averaging 6000ft.
    If I change the jetting and needle as per JD recomendations.
    Will I still need to drop the needle correspondingly or will it be a trial an error thing?

    The bike's being shipped out from UK to Alburquerque and would obviously prefer it to be set up beforehand, although I will take a selection of jets and both needles this time.
  7. bmwktmbill

    bmwktmbill Traveler

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    Beek and Timo,
    You are both right.
    About carbs and flow I really don't know.
    Hey that rhymes.

    I go back in time to the flow bench and Sonny Branch making Harley's go fast on the flat track.

    Out of all that I got it that air is an invisible, compressible fluid.
    So birds fly and so do airplanes and I always loved the look of a velocity stack.
    Air flows like water. It's a fluid. Birds swim in the air.

    Being a fly fisherman I spent many years of time watching water.
    It flows and is predictable in my experience.

    That said, we understand that KTM used a BST on the 640 travel bike because the Adventure was not designed as a racer. The BST is a carb that self adjusts to altitude changes and is a frugal user of fuel.

    If I was running a FCR carb on a 640 Adventure I'd have to see the layout of the 660 racer's airfilter and airbox, I'd build that as best I could....

    The factory always cheats.

    They use a dyno.

    As for dirt, no worries, chrome bore and chrome rings.
    The foam filter in my experience doesn't pass dirt, it will plug eventually but it is easily cleaned with tank gas and oiled using a bread bag, engine oil and some EMT gloves.
    FWIW.

    bill
  8. Droptarotter

    Droptarotter Long timer

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    Bill;
    So many words of wisdom here.........I forgot the name "Sonny Branch" and all the flow bench secrets that man revealed.

    For me......my BST with only 3000km's on it works fantastic!........I'll use it until it gives me problems then I will install an FCR because I don't change altitude that much.

    As for dirt........the foam air filter only gets more efficient
    the dirtier it gets.........all you have to do is clean it to get more performance!


    Cheers
  9. bmwktmbill

    bmwktmbill Traveler

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    Thanks Drop,
    It's a little weird to say, "Mom, I'm just trying to understand the aerodynamics of a compressible fluid. Just let me read for another hour."

    "Please???"

    [​IMG]

    Life is so strange.
    North of the 45th parallel in March.

    Is wind just a gravity storm?
    Or a lion or a lamb?


    bill
  10. Young-Gun

    Young-Gun KTM Tragic

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    Psychic Vampires?
  11. johnno950

    johnno950 Long timer

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    00 660 airbox-40mm dellorto
    [​IMG]
    07 690rr airbox-41mmfcr
    [​IMG]
    the rallyes got a fair bit more punch hp wise,air inlet only part of the sum,bigger exhaust/bore,stroke........amazing bikes
  12. bmwktmbill

    bmwktmbill Traveler

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    Be on the alert, they are fucking everywhere.
    And dead.
    Just look at the top of every empire.

    Energy thieves.
    They steal joy.
    They want to destroy my KTM and make me ride a KLR.
    bill
  13. bmwktmbill

    bmwktmbill Traveler

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    I think we are getting somewhere.
    Thanks for the pics.

    What bolted on top of the 660 box, I see the inserts or something in the corners.

    bill
  14. johnno950

    johnno950 Long timer

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    The 2 660s 99 and 00 i owned never had anything that bolted fitted onto the 4x threaded inserts,had a fine mesh screen on rear and side from memory,i believe this airbox on the early rallye 98-00 was generic with a 620 super comp/and a few of the other lc4 models,fairly sure the 690 rallye air box is generic with the 01-06 660 rallyes,looks the same,never cross/refed the part numbers....01-06 had a 39mm fcr the 690rr has a 41mm,my 690 has alot of induction noise...love it
  15. bmwktmbill

    bmwktmbill Traveler

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    Thanks for the info and I appreciate your comment on the induction noise. I always thought that was why they put the snorkle on the 640. To quiet it.

    That's why IMHO Sommer opened the side of the airbox with a screen.
    For German legal reasons they couldn't pull the snorkle even though it made sense to do it that way.

    I might be wrong about that, anyway Sommer had a dyno.
    bill

    BTW, if you think we are nuts you ought to get into a debate with kayakers(just laid out cash for a used Kevlar boat) on hull design. It's really the same debate except water is a non-compressible fluid for all practical purposes.

    Go with the flow!!

    http://www.paddlewise.com/topics/boatdesign/pro-conswede.html

    It's all here...

    http://archive.org/stream/speedpowerofship00tayluoft#page/n9/mode/2up

    Stream lines.

    Which brings us to one of my favorite songs.

    http://www.youtube.com/watch?v=28yUf5l6egw

    b
  16. overlandr

    overlandr Dystopist

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    Now I can see why cycling is so popular there in the Netherlands!

    Yeah Bill, Sommer had a wealth of experience on KTMs and its a pity they were bought out, rebranded and effectively disbanded. I saw a DB killer insert for an akra system the other day that had been modified by them with some small annular holes drilled to increase the gas flow. I think jerome was told that they recommended the FCR41mx in preference to its smaller cousin.

    One can still download their old catalogues (with their infamous tips) in German for those interested from the new company's site.
  17. bmwktmbill

    bmwktmbill Traveler

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    Overlandr, Got a link to the new site?
    bill
  18. DaddyBigDaddy

    DaddyBigDaddy AKA -Evel Kneilson

    Joined:
    Sep 24, 2004
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    Location:
    Liberal ShitHole, San Fran-sissyco, Kalee-Fornee-a
    Looking for a 640A dual disc wheel or hub

    Email Ken@AspenRacing.com if you have one or know where I can get one

    THANKS! DaddyBigDaddy
  19. overlandr

    overlandr Dystopist

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    If you go to their old site - ktm-sommer.de I think, it auto redirects you through to their new owner's site and there you'll find :

    http://www.ktmteamwest.com/website/index.php?option=com_remository&Itemid=399

    The 4th line is sommerkatalog2008 and has 29 separate downloads - get downloading, man! Lukas was going to translate the "Sommer tipps" but that was some 5 years ago before he moved on from our 'dinosaurs'!!


    I've just tried google translate on an excerpt about needle and jet wear on a carb. This is the result which is quite usable :

    "NEEDLE and needle jet
    The wear on the needle (all carburetor)
    and needle jet (all carburetor)
    can not be measured, since the needle conical
    is formed and the inner roundness
    The needle jet is not measurable.
    By constant friction and
    Hitting the needle (caused by
    Vibrations) in the needle jet is formed
    Also here is a material reduction in
    two components.
    Is the more down in the "basement"
    (Off), the higher the wear out
    Full load is virtually no wear
    instead. Why can not an exact KM
    Give indication for the exchange.
    Packages should be at a LC4
    Replace every 20,000 km (needle and
    Needle jet), 4-stroke KTM Racing latest
    every 2nd Season, KTM 2 stroke each
    Season (needle) occur."
  20. bmwktmbill

    bmwktmbill Traveler

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    Overlandr,
    Thanks for the link.
    How did you get Google to translate in the pdf.
    Did you use google chrome?
    bill