KTM 950 Jetting Database

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

  1. JakesDad

    JakesDad Adventurer

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    I recently swapped out the 950 engine for a 2012 990 adventure engine. That year has the larger Super Duke 990 cams it. Got the 990 engine buttoned up last week and worked out a few bugs since. Got it to the dyno today and it did about 10% better than the last time I had the 950 dynoed. Same dyno at the same shop as last time. 2 years difference. I wish I had come in and had it run in the last months before I swapped the engines. It would have been good to see what the HP had gone down to. It didn't feel as good as it used to.

    I left the jetting the same to see how it would do. I definitely need to get a touch richer in the middle to upper range. I would love to think that it will make a few more HP when I do that, But I know my luck. The old adage that it will never feel as fast as it does right before you melt a piston. I did have to go to 5 turns out on the flex jets where as I used to be about 2.5 turns with the 950.

    Mods are:
    990 in a 950
    Q4 slip-ons.
    emissions all gone.
    Rottweiler intake.

    Jetting is:
    165 front
    170 rear
    45 pilot
    Factory Pro needle at 4th clip notch.
    5 turns out on the flex jets.

    Any insight into what my best avenue to lower the AFR would be nice.
    Sadly the Tachometer pickup cable wasn't working this time so they did the graph in MPH not RPM. The last time it was RPM so the graphs aren't laid over each other well. Annoying, but what can ya do? The redline is the same for both lines so try to imagine it that way.

    JohnDyno-page-1.1.jpg
    Bonnie & Clyde likes this.
  2. opanos

    opanos Been here awhile

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    It seems to be something wrong with those numbers... And dynos seem to be done with different gear!
  3. horizonchasser

    horizonchasser Been here awhile

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    Has anybody tried a Lectron (jet less) carby on a LC8 ? Is it possible?
  4. opanos

    opanos Been here awhile

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    Hi
    After a lot of experimenting with carbs on the big katooms, I would say that there is no reason trying anything else on this bike besides experimenting and nothing would work better that the stock CVs.

    Lectron is basically a 2 stroke carburetor, with no acceleration pump (means that it won't stand wot at low engine revs), has the most basic slide operation system (the one used in small moppeds and old bikes without return cable) and the fact that it has almost no jets is it's main downside. Fuel delivery is adjusted by the needle profile, which means that if you have a problem in a specific throttle position area, you need to change needle (which is expensive, and multiply every swap by 2)

    The ''best'' available alternative by now is that FCR kit, provided by sudco. Which is far from refined compared to the stocks and deliver much worse performance overal besides other MANY problems they bring with.

    As far as I can think, the best real alternative is the Mikuni TDMR, and that because we are restricted to a downdraft configuration. Basically the same carb as the FCR, but more modern and far more refined. But in order for those to work on our lc8s, they need some development (as the FCR kit needs). It needs a linkage arangement in order to be able to operate both slides simultaniously and sync them properly, and some adaptors in order to be able to use them on our engine, either with pods, or better, with the stock airbox and air filter.

    This would of course require a lot of money in deveoping and prototyping. Some years earlier, i think there would be a market that could support that. For example, invest some money and adapt them in the 950/990, and then sell a complete kit. Nowadays, carbs are a dying tech and even the later 990s have become relatively old bikes too, and most people aim at the newer 790/1290s and no one really cares about the older bikes, besides some romantic people like us.

    It would be really great to have a kit like this and I would definitely be interested, but there is really not a lot of people interested in supporting such a thing.


    [​IMG]
  5. horizonchasser

    horizonchasser Been here awhile

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    Ok, thanks Opanos,was just a thought.Cheers .
  6. JakesDad

    JakesDad Adventurer

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    Same gear but different sprockets. I was totally stock sprockets in the first dyno. I was down 2 teeth on the front sprocket in the new dyno. The bike is back to stock tooth count since then.
    Had I realized that this was gonna happen I would have changed them before the dyno. But I expected the rpm pickup was gonna work as it should and I'd be set even with a slightly different tooth count. I'm gonna call them now and see if the rpm pickup has been fixed since then. I'd love a torque graph and a rpm standard on the graph.

    Thanks!!
  7. opanos

    opanos Been here awhile

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    What type of dyno is that? Is it a bit pessimistic or is there something wrong with your config? Also, is there an afr chart available? Dyno charts without an afr chart are pretty much useless. What jetting did you use for which engine? The one mentioned on the dyno chart?
  8. JakesDad

    JakesDad Adventurer

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    Heya Opanos.

    It's a dynojet dyno. I presume by pessimistic and asking if the bike is ok you're implying that the hp numbers seem low. I'm not sure what I should be dynoing at here in the phoenix area when it's a bit cold. Not many people dyno their bikes. And of that small group very few have done 990/carb swaps into a 950 chassis. I had hoped for more power and think there is some hiding in there. Jetting needs to change some. Gets super lean up top.
    The afr chart is part of the graph I posted. The red lines are the new dyno run, blue is an old run with the 950 engine. 2 lines of each color. 1 of each is hp, the other of each is afr.
    Both dyno runs had the same jetting. I mention them in my post with the graphs.
    Thanks
  9. ManuC

    ManuC 950 SM

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    NEEDLES TO RICH TRY 2.5
  10. NVTS

    NVTS Are you ennen oh eff tee Supporter

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    My SE is backfiring only during warmup. It runs well up top once warm.
    I have recently changed the intake and jetting but nothing is way out of spec.

    I have not balanced the throttle bodies or checked TPS. could either of these be the cause?
    1000ft Above sea level
    Rottweiler filter
    Akras w/ DB killers in
    175/180 mains
    45 pilots
    OEM needle clip # 3
    Floats 2mm
    Air screw 2 out
    NVTS
  11. KSPLS

    KSPLS Adventurer

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    This may be a revival of an old thread but this forum has helped me sort my jetting immensely.

    2006 950 Adv. @ approx. 700 feet ASL
    Stock air-box
    All vacuum lines plugged (synched carbs with a synchrometer) WAY easier than fiddling with my Motion-Pro carb-synch tool.
    FP titanium needles on center clip
    Stock mains
    FP 45 pilots
    Flex-jets @ 2 turns out
    10"/11" bowl vents
    2 into 1 Remus Revolution slip-on
    BMC air filter with pre-filter
    Idle screw and Flex-jet knobs routed through left side access door on air-box. I did not take pics but the door is modified with 3 holes drilled and sealed with grommets. A possible concern with this modification is the carb linkage contacting the idle/air-screw cables but I ensured they are clear of any interference. Sealed previous holes in the bottom of the air-box with JB-weld.
    I can access the carbs with removal of left side tank only.

    Bike runs perfect with this set up. No surging, very minimal popping from the exhaust on deceleration, and pulls perfect from idle to redline. Have yet to determine MPGs. It will power wheelie in 2nd gear if I back off throttle and give it the beans.

    Attached Files:

  12. armstrongracer

    armstrongracer Adventurer

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    I'm in middle of sorting a starting issue on a 950sm and tidying up the jetting which has something to do with the bad starting. Everything was very rich and TPS was out of adjustment also. I've an X-bikes set up (DNA type filter, no snorkles or windows). My factory set float height was 2-2.25 (upside down). I like my bikes set on the lean side with crisp throttle response, which is how I always set my race bike up so I'm going for a Mousitas type setup with the needle at 1.5. Which leaves me with a spare thin washer. I don't want to lose it as I may have to go richer on the needles, so does anyone see any harm is putting it above the clip & under the thick washer, I cant see any problem with this, but there may be something I don't understand about CV carbs.
  13. opanos

    opanos Been here awhile

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    yes, do it like that....will not affect your carbs in any way
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  14. armstrongracer

    armstrongracer Adventurer

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    Cheers, worked a treat. Starts on the button hot or cold, really crisp throttle response, no pops or bangs when I crack the throttle.
  15. bigborett

    bigborett Hipster

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    Question about balancing the throttle bodies with a vacuum pump fitted.
    My pump is connected to one of the vac lines. Is it ok to still check the balance of the lines but putting a T in the one with the pump connected or do I need to go another route?
    I don't have flow type meters so going the fluid type balance meter, one I made up years ago.
  16. Zuber

    Zuber Zoob Supporter

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    The only difference should be that the one line will not pulse as much. You should have some small restrictors in the vacuum line to keep the pulses down. Otherwise, the fluid columns can get broken and make the readings off. I've inserted old carb jets into the line as restrictors.

    I like the TwinMax electric gage. Very accurate and you can ride the bike with it installed.
    bigborett likes this.
  17. Zuber

    Zuber Zoob Supporter

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    With the #45 low speed jets, I'd guess the bike will run better with the Flex-Jets turned out 3/4-1 1/4 turns.
  18. KSPLS

    KSPLS Adventurer

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    I suppose I could give that a try. the bike runs excellent at the moment.
  19. Zuber

    Zuber Zoob Supporter

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    One of my quick tests for these mixture screws - start the bike cold and immediately turn off the choke. The bike should run poorly and very lean since it's cold. If it runs clean, then it's too rich.
  20. KSPLS

    KSPLS Adventurer

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    Thanks, appreciate that tip.