KTM 950 Jetting Database

Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by Billroy, Jan 11, 2006.

  1. Billroy

    Billroy Billroy

    Joined:
    Nov 28, 2005
    Oddometer:
    41
    Location:
    Edmonton, Alberta, Canada eh!
    On another forum I hang out (Thumpertalk) someone started a thread for a particular model that indicated what people were using for Jetting settings and their elevation etc.. It was a very helpful thread because, by the time everone entered their parameters, you could search and pretty well find some good settings that may help narrow the jetting settings for your own bike based on other's exprience. I've searched and read most of the jetting threads including "FP..cure for what ails your carbs" and it is all helpful. (But not everone has access to a good performance shop with a dyno, CO analyser so) I'll start and hopefully others will add theirs until we have a good set of data for the KTM950. Please indicate any parameters you have that may affect jetting and include how well you think your set-up is:
    (ie: elev, aftermarket exhaust, airbox mods, etc.)
    KTM 950 Adventure:
    Elev: 2500ASL
    Exhaust: Staintunes
    Airbox mod: stock
    Canister and SAS: gone (I don't think these affect jetting but oh well)
    Main jets: stock (155/160)
    Idle jets: stock (42)
    Needle type: stock
    Needle clip: pos 3
    Mixture screw: 2.25 turns

    Not quite optimum, top end is excellent, low/mid throttle response has hesitation.

    Please add your settings.
    #1
  2. jlehtinen

    jlehtinen n00b

    Joined:
    May 9, 2005
    Oddometer:
    5
    KTM 950 Adventure: 2004
    Elev: 0m ASL
    Exhaust: Sebring race carbon cans
    Airbox mod: stock
    Canister and SAS: stock (european version)
    Main jets: stock (155/160)
    Idle jets: stock (42)
    Needle type: stock
    Needle clip: pos 3
    Mixture screw: 1.5 turns out

    Bike is running great! No hesitation what so ever, and choke is needed in "cold start". :clap

    Jyrki
    #2
  3. Jeepboy

    Jeepboy Roost

    Joined:
    Feb 9, 2005
    Oddometer:
    560
    Location:
    Champaign, IL
    KTM 950 Adventure S: 2004
    Elev: 790 feet
    Exhaust: Remus Carbon silencers with insert removed
    Airbox mod: yes
    Canister and SAS: removed
    Main jets: 165/170
    Idle jets: stock (42)
    Needle type: stock
    Needle clip: pos 3
    Mixture screw: 2 turns out

    Idle speed wanders, I'm going to get some 45 idle jets to see if that will fix it. Otherwise the bike runs awesome!
    #3
  4. Billroy

    Billroy Billroy

    Joined:
    Nov 28, 2005
    Oddometer:
    41
    Location:
    Edmonton, Alberta, Canada eh!
    Thanks for adding your settings. I think it is helpful info for other 950 owners. Hopefully others will contribute.
    #4
  5. RedFlash

    RedFlash Go Cubs!

    Joined:
    Feb 10, 2005
    Oddometer:
    2,440
    Location:
    Home of the Chicago Cubs!
    KTM 950 Adventure S: 2005.5

    Elev: 600 feet, ASL
    Exhaust: Wings with 28mm insert (NFS style)
    Airbox mod: yes
    Canister and SAS: removed
    Main jets: Stock (158/162)
    Idle jets: stock (42)
    Needle type: stock
    Needle clip: Third position from top
    Mixture screw: 2 turns out

    Slight flat spot coming off idle, and will install 45 pilot jets next time in the box (K2M suggestion :deal ). Runs strong to redline. Getting about 38 mpg all-around. Have had 42 mpg just running open highway (~75 mph).

    Addendum: Air jets are stock (per a request further down...:D )<!-- / message -->
    #5
  6. K2m

    K2m ....58....

    Joined:
    Feb 27, 2005
    Oddometer:
    2,238
    Location:
    Sydney Australia
    #45 @ .25 (Factory Pro)

    2nd clip (stock)

    142.5 & 145 (Factory Pro)

    Everything else stock........ well almost...

    295km per 20lt (big increase) X 3 tanks so far

    idle = 13.4:1

    light throttle cruse = 13.7 to 14:1

    WOT windup = 12.7 to 13.2:1

    Sudden snap open 11.8 then to 13s

    Haven't been touring yet.....

    This thing is so good to ride...... but difficult to resist lifting it :ricky

    Hi Redflash :wave
    <!-- / message -->
    #6
  7. Billroy

    Billroy Billroy

    Joined:
    Nov 28, 2005
    Oddometer:
    41
    Location:
    Edmonton, Alberta, Canada eh!
    K2M,
    I notice you have leaner mains than stock. What elevation are you riding at? Stock cans and airbox not modded? I understand the Oz bikes have individual carb vent hoses (not connected in airbox by Y) vented out the bottom of the airbox in the V with no vent filters. Is that how yours is vented?
    #7
  8. RedFlash

    RedFlash Go Cubs!

    Joined:
    Feb 10, 2005
    Oddometer:
    2,440
    Location:
    Home of the Chicago Cubs!
    Back atcha :wave K2m!!
    #8
  9. K2m

    K2m ....58....

    Joined:
    Feb 27, 2005
    Oddometer:
    2,238
    Location:
    Sydney Australia
    Sea level,

    Vent hoses = Yes. There is a TSB on this as it was changed from the 03. I will scan my parts manual tomorrow, and put it up.

    A well tuned CV carb will not notice air box mods. That's the beauty of CVs they self compensate, but they must be tuned correctly first.

    Exhaust mods effect cylinder scavenging..... altering the power and torque. so long as the AFRs are between 12.5 and 13.2 at maximum torque there should be no problems. Stock cans are the correct tuned length (as designed) with the pulse being generated on exit of the CAT inside the can. They need to be opened to 50mm for the exit pipe.

    So there's the answer...... clear as mud eh

    All my tuning was done with a Wideband..... and a big collection of jets.
    http://wbo2.com/ Have fun :D
    #9
  10. Motomedic

    Motomedic Over-caffeinated Raconteur Supporter

    Joined:
    Oct 4, 2004
    Oddometer:
    3,538
    Location:
    Spokane
    No dyno/sniffer tests yet, but here it is:

    04 ex-demo bike
    Sea level (200ft =/-)
    FMF Q silencers
    SAS/Canisterectomy
    stock main/pilot jets
    needle moved up one clip (2nd groove?)
    stock airbox

    No backfiring/decel popping, and seems to run like a crackhead with a hot TV! I rode a friends bike after he spent lots of dyno time with a similar set-up (FP Jet kit, airbox modded, FMF's) and my "SOP Dyno" couldn't tell much difference. Maybe a little better throttle response, but hard to quantify. Certainly more intake noise.
    #10
  11. ephemeris

    ephemeris UYPL

    Joined:
    Sep 3, 2005
    Oddometer:
    663
    Location:
    N44*03.075' W123*05.856'
    There's a trend here - Nobody is listing their air-jet size?

    KTM air jet options: 70, 80, 90, 100 - stock is 80.
    KTM pilot options: 42

    When people bump the pilot to 45, it appears to take the range of adjust out of the air screw. Wouldn't an air screw setting range of 1.25 - 2.25 turns out be desirable?

    Has anyone with a 45 pilot tried a 90 air jet?
    #11
  12. ktmnate

    ktmnate Long timer

    Joined:
    May 7, 2003
    Oddometer:
    3,092
    Location:
    Somewhere
    '05 actually it's an '04.5

    Akra Ti
    needle 3rd position (in the middle)
    165/170 mains
    sea level
    mixture set at 1.75 turns
    no other adjustments to the carbs

    all the emisions stuff removed and replaced with tubes for fixing flats. It runs awsome. I use it with the inserts out of the exhaust usually but it runs good both ways.


    Nate
    #12
  13. motoman250f

    motoman250f Been here awhile

    Joined:
    Aug 21, 2004
    Oddometer:
    808
    KTM racing exhaust
    sommer airbox mod
    factory pro 45 pilot
    factory pro needle in #2 (recommended)
    factory pro 172/168 mains
    factory pro recommended 2.5 turns on air screw
    carbs vented right under airbox
    stock air jets
    smog stuff removed with cyl covers
    1500 ft.



    will get 42 mpg if i baby it. No dead spots, just fast and great throttle response. Much better than stock jetting however I think the 45 pilot is the key to any of my jetting success.
    #13
  14. Billroy

    Billroy Billroy

    Joined:
    Nov 28, 2005
    Oddometer:
    41
    Location:
    Edmonton, Alberta, Canada eh!
    motoman250,

    What elevation do you ride? Do you know how many turns out on mixture screw?
    #14
  15. RedFlash

    RedFlash Go Cubs!

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    Feb 10, 2005
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    Home of the Chicago Cubs!
    Bumpitolla!
    #15
  16. RAGrote

    RAGrote Fishin w PICO

    Joined:
    Nov 1, 2004
    Oddometer:
    1,034
    Location:
    Colorado fire road wandering....
    The 45 is used, I believe, to add fuel to partial throttle openings. The 45 maybe a little rich @ idle but I think it should be about perfect @ partial throttle AND (even more importantly IMO) the transition to the mains should be smoother. Again - IMO.

    Mine? STOCK - but not for long. When I get the carbs out for valve adj. I'll throw in the 45 pilot. Then I'll adjust for good idle.

    What's your thinking behind the 90 idle air cutoff jet? If you don't mind my asking.

    One thing NOBODY has talked about is fuel height. How many of us have checked the float height? SUPER important!!! Seems like it's been left out of the equation..
    #16
  17. ephemeris

    ephemeris UYPL

    Joined:
    Sep 3, 2005
    Oddometer:
    663
    Location:
    N44*03.075' W123*05.856'
    I've got 70 air jets on order, and richer/leaner mains.

    My thought process is KTM basically has two reasons not to list optional pilot jets.
    1) Emmissions regulations.
    2) Air jets, needle, and mains will provide the needed mixture correction.

    I've always felt the air screws should have a reasonable range of adjustment, that indicates to me that the carb circuits are performing within their intended range. Thus harmony and linear power delivery over a broader altitude range.

    Regarding the 90 air jet, if the circuits overlap the 90 would counter the 45 pilot and possibly allow an air screw range of .75 to 1.50. Don't have a schematic of the circuits so this is a guess.

    KTM USA does stock non USA parts, such as Euro lights and switches yet they don't stock a 45 pilot?

    NOTE: I'm in no way shape of form an expert on tuning! Though I have owned cars with dual DCOE Webers and did my own tuning on them.

    I'm heading over to central Oregon to go ride the 2 stroke tomorrow, I wouldn't want to make that trip if my air screw as at one extreme or the other. Altitude, moisture, and humidity can dictate .5 turns either way.
    Going from 3,200 to 6,800 ft it's nice to have adjustment. (Not that it's a trail side option with the 950)
    #17
  18. K2m

    K2m ....58....

    Joined:
    Feb 27, 2005
    Oddometer:
    2,238
    Location:
    Sydney Australia
    "ephemeris" If I sett the #45 pilot to idle at the same AFR as the #42, it would be between 1.0 and 1.25. You will not often need the chock to start. Its my personal preference to idle as lean as possible. There is no compromise with this setting. I have a rock solid idle. Since I finalised these changes I have not touched the settings, not even the idle.

    I'm sure that changing this air jet will eliminate your flat spot, and I was interested to note that Autostream recommends 1.5 turns out.

    For me the #45 gives smooth controllable throttle response. This important "transition" area. This can be at any RPM. When you are cranked over at 5000 RPM in second gear at an intersection on a wet road with a feathered throttle...... This is where the #45 is superb at controlling the engine inertia. It just makes the bike a pleasure to ride.

    We look forward to your comments on the air valve change. Auto knows his stuff. I'm sure it will be an big improvement.
    #18
  19. ephemeris

    ephemeris UYPL

    Joined:
    Sep 3, 2005
    Oddometer:
    663
    Location:
    N44*03.075' W123*05.856'
    K2m,

    Appreciate your descriptive input regarding power delivery.

    I contacted JD Jetting hoping that he may be interested in testing and developing needles for the 950. Regretefully he didn't sound real interested. "We have not made kits for the 950 at this point. We have access to a bike and may in the future as time permits. The carburetors are a lower perfomance street version than our other kits."

    Too bad since the needles he produces for the off-road 2 & 4 strokes are money when it comes to transitioning from idle/pilot/main circuits.

    Thanks to JD's needle I can't wait to ride the 200E tomorrow, that little motor pulls like a freight train now. Wet desert floor, high bermed serpentined fast trails with nervana like traction provided its not frozen.

    I propose a toast to all those partaking in the endless search for jetting perfection!
    :beer
    #19
  20. Billroy

    Billroy Billroy

    Joined:
    Nov 28, 2005
    Oddometer:
    41
    Location:
    Edmonton, Alberta, Canada eh!
    Here's to jetting perfection!

    I have the FP kit in my grimey little hands but will not install any pieces until I have read every post on jetting. Currently still sitting with stock carb settings except for needle raised one clip position (3rd). Since raisiing the needle (and installing staintune exhaust) I have no throttle response below 4000 rpm (no bottom end). Still researching....
    #20