2006 640 fuelling ish

Discussion in 'Thumpers' started by G-three, Apr 14, 2006.

  1. G-three

    G-three Adventurer

    Joined:
    Dec 9, 2005
    Oddometer:
    37
    Location:
    Victoria, B.C. Canada
    Wow, this first post thing feels good. i just picked up a new 640 adv. in march, and love it. after riding a klr for 10 years, its a shock to have not bought the ktm earlier. However, right from day one the bike when left to idle for 20sec to a minute, like at a stop light, would hesitate and sometimes stall when light throttle was applied, like leaving the light. So i figured the bitch was just choked down. During the first service I opened the airbox with a cover like the ktm jobby, re- jetted to a 157.5, which will change to a 160 as i found a lean condition after the plug was checked, raised the needle one clip, drilled slide holes to .117 and hogged out the stock exhaust. The bike starts and idles fine, and under way there is a dramatic improvement over stock, but the stalling problem still persists, if anything it is worse. Next, i turned up a mixture screw like loadeds and played with it. Got a smooth idle, but it did nothing for the problem. So, is it the float level? the bike works awesome. Is it the pilot jet? Do I need to go up size? Any help would be awesome, thanks
    #1
  2. creeper

    creeper Still alive...

    Joined:
    Dec 13, 2003
    Oddometer:
    10,718
    Location:
    Puget Sound
    The occasional "flame-out" is fairly common with a new, tight LC4. Break-in can take a few thousand miles.

    You didn't mention what your idle speed is... if its around 1400-1500 rpm, it's a bit too low.
    Try raising your hot idle speed to 1600-1700 rpm... too low an idle speed will tend to exacerbate the problem.

    When the idle speed is set correctly, the low speed mixture screw will become a bit more "responsive" to adjustments.
    At your elevation, the idle mixture screw should be set at around 1.5 to 2.5 turns out from seated.


    C
    #2
  3. Buckster

    Buckster Banned

    Joined:
    Jul 23, 2004
    Oddometer:
    1,003
    Location:
    Atlanta GA or London UK
    Could be the carb breather pipe getting pinched under the seat.
    #3
  4. G-three

    G-three Adventurer

    Joined:
    Dec 9, 2005
    Oddometer:
    37
    Location:
    Victoria, B.C. Canada
    Creeper, thanks. I'm relieved. Idle was set to 1500 as per the manual, I'll try 1700- 1600 and check it out. I'll try to post some pics when I figure it out.
    #4
  5. meat popsicle

    meat popsicle Ignostic

    Joined:
    Feb 9, 2004
    Oddometer:
    14,355
    Location:
    Circumlocution Office of Little Dorrit
    I second the Buckster's emotion - did you check the "evaporative emissions control" hardware? You didn't state that you have either checked or removed it.

    From memory a few have had a similar issue and found it to be a pinched line. I don't know much about the fancy SAS system (sic?) on the 04- bikes but folks have been removing them in order to get the engine breathing properly and reliably.
    #5
  6. G-three

    G-three Adventurer

    Joined:
    Dec 9, 2005
    Oddometer:
    37
    Location:
    Victoria, B.C. Canada
    Haven't removed the emissions control crap yet. seems to have a line from the carb and one from the airbox to the canister were the tool pouch should be and a breather line which runs from the canister to the front of the bike under the tank. Can i remove this crap and plug the holes on the carb and airbox or will it affect the fuelling? as far as venting on the carb itself, all i see is a short 90 degree tube with a breather on it, no way it gor pinched since it sits below the seat inside the frame tubes.
    #6
  7. G-three

    G-three Adventurer

    Joined:
    Dec 9, 2005
    Oddometer:
    37
    Location:
    Victoria, B.C. Canada
    ok forget the carb vent stuff......got a couple of the lines confused and i can see the one that could be pinched...sorry.
    #7
  8. meat popsicle

    meat popsicle Ignostic

    Joined:
    Feb 9, 2004
    Oddometer:
    14,355
    Location:
    Circumlocution Office of Little Dorrit
    G-three,

    There are a few guides available for dealing with evaporative emissions devices (not sure about the SAS stuff that your model year has... probably somewhere) and discussion about the carb vents.

    But, DO NOT, I repeat DO NOT go about willy-nilly cutting and blocking off lines and vents... most are there for a good reason.

    (sorry, but I am a practicing parent; you just were my test subject :D)
    #8
  9. G-three

    G-three Adventurer

    Joined:
    Dec 9, 2005
    Oddometer:
    37
    Location:
    Victoria, B.C. Canada
    ok, so the lines are as follows, canister has one line venting through the snorkel(its just stuffed in there), one line running under the tank to the front of the bike under the front fairing(to nothing) and one line on the opposite side running to the airbox btween carb and filter. dosen't look like it does much, so i'll plug the airbox and see how it runs. carb has vent tubes that are not attached to the canister, nor is there a pipe attached to the cylinder head betwwen the exhaust.
    #9
  10. meat popsicle

    meat popsicle Ignostic

    Joined:
    Feb 9, 2004
    Oddometer:
    14,355
    Location:
    Circumlocution Office of Little Dorrit
  11. shardzero

    shardzero I have a bike.....

    Joined:
    Aug 30, 2005
    Oddometer:
    490
    Location:
    Perth
    The bike is designed to run with the emission control installed so I would try less drastic measures first. Here in Aus we have issues with fuel quality. Basically results in certain fuels making my bike run like a pig. Maybe try several servos and even a fuel additive.
    #11
  12. meat popsicle

    meat popsicle Ignostic

    Joined:
    Feb 9, 2004
    Oddometer:
    14,355
    Location:
    Circumlocution Office of Little Dorrit
    Have you looked over the tubing system that KTM installed with the charcoal cannister?

    It's helter-skelter at best; and quite a few have had issues with it becoming pinched, likely due to it's factory routing, or when the bike is on it's side the charcoal cannister fills with fuel -both problems interfere with operation.

    There has been no posts (save yours) that counciled to leave the charcoal cannister in place. There is, however, a difference of opinion in regards to the SAS system. Although I don't have experience with this (not part of the 2003 models), some say it excessively leans out the mixture under deceleration, causing popping, whereas others say it's no big deal. Probably relates to bike setup. :dunno
    #12
  13. G-three

    G-three Adventurer

    Joined:
    Dec 9, 2005
    Oddometer:
    37
    Location:
    Victoria, B.C. Canada
    removed the canister. totally rinky-dink. i can't honestly say by looking at the setup that it will effect the way the bike runs, but i'll let ya know.
    #13
  14. creeper

    creeper Still alive...

    Joined:
    Dec 13, 2003
    Oddometer:
    10,718
    Location:
    Puget Sound
    It has no effect on the way the bike runs at all, other than it may run better if the fuel tank vent is routed to a location less likely to be pinched.

    The EVAP canister is not an "invasive" component... all it does is to use airbox vacuum to gather and contain evaporative emissions in an activated carbon medium.

    C
    #14
  15. G-three

    G-three Adventurer

    Joined:
    Dec 9, 2005
    Oddometer:
    37
    Location:
    Victoria, B.C. Canada
    so....the bike works awesome. removed canister, 160 main jet, stock needle position, air screw 1.75 turns out. idle set to 1650-1700. no hiccup
    , or stall. i wonder if the canister system was causing a rich condition when left to idle causing the flame out?
    #15
  16. joekanter

    joekanter Been here awhile

    Joined:
    Nov 7, 2007
    Oddometer:
    128
    Location:
    North Western Nevada
    Now that I know he difference between the SAS (which I don' have) and the canister thingy (which Master Meat gently informd me that I do have). What should I do with the three lines going to the cannister? Do I simply plug them? Or is there a more complictaed procedure? Thanks guys in advance.
    #16
  17. gunnerbuck

    gunnerbuck Island Hopper

    Joined:
    Nov 19, 2005
    Oddometer:
    5,139
    Location:
    N.V.I, B.C.
    Unplug the three lines... Follow the one to the airbox, unplug from airbox and put some kind of cover or plug over the remaining spigot.... Put a tube into the steering pivot hole and run it to your gas cap vent.... Make it long enough so it reaches through the bottom just clear of the high fender if you have one....
    #17
  18. joekanter

    joekanter Been here awhile

    Joined:
    Nov 7, 2007
    Oddometer:
    128
    Location:
    North Western Nevada
    Cool-thank you. And thank you for not slamming the noob.
    #18
  19. ChrisC

    ChrisC Amal sex?

    Joined:
    Feb 25, 2003
    Oddometer:
    6,320
    Location:
    Prescott, Arizona USA Earth
    Your time will come... :evil
    #19