New 950/990 air filtration system development

Discussion in 'KTM 950/990' started by alongat, Feb 9, 2019.

  1. Maoule

    Maoule Long timer Supporter

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    I guess I wasn’t very clear... I am switching from a stock airbox and filter. The MPG, jetting and sparkplugs I referenced were from that setup, not an existing foam filter or the new Tripleclamp filter. I understand that I will be rejetting for the new setup. BTW, I installed the H2W flexjets kit over a year ago and have been, for the most part, satisfied. Now that I have clarified where I am, let me further mention that I have a basic understanding of carburation. I plan to proceed carefully especially not to hole a piston or two. But I would like to have a decent starting point to avoid pulling the carburetors too many times.
    I have gathered here and the tuning method thread the following: 172 and 175 mains(I have additional sizes as well), up to 3 turns on the flexjets, 3rd groove on the needle and 3 -3.5mm on the floats. Any additional useful changes to make while everything is apart? Thanks
  2. opanos

    opanos Been here awhile

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    170 175 mains
    Needle on 2nd groove, 3rd is really a bad idea
    3mm float height
    45 pilots
  3. mookymoo

    mookymoo Mookish Mook

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  4. Maoule

    Maoule Long timer Supporter

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    I finally got everything back together...I had a work trip for a week, then while reinstalling the radiator, I kinda dropped it and bent the bung for the upper drain plug bolt which put a small crack in it, which I discovered after putting everything back together and filling the radiator. The next thing was the orings for the fuel infeed fittings. Removing the keeper plate was a PITA. Why are those screws made in China and redlocktited, FFS? I replaced them with some hex bolts. Then I chased all over for orings, finally locating some at them Yamaha shop.
    I adjusted the flex jet to 3 turns and balanced the carbs. My initial settings are:
    170/175 mains
    45 pilot
    2 groove needle, thin washer beneath clip
    3mm float

    It runs like a cat with a tin can tied to its tail!
    3rd gear power wheelies! Very urgent throttle response. The intake noise was noticeable but not as bad as the itg setup on my 990. This was just a quick run around the neighborhood... I plan to get out this weekend for extended testing and get an idea of the fuel consumption, etc.

    BTW, I couldn’t figure out how make the plastic keeper washers work in any useful way. Are they supposed to go up on the unthreaded part of the bolt between the frame and the filter ‘grommet’?
    Dusty and opanos like this.
  5. opanos

    opanos Been here awhile

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    I have ended up to that jetting after a lot of experimenting with wb sensor.

    Your pilot now is super rich, so try adjusting flex jets to 1 turn... Also, i think that front cylinder idles slightly leaner than the rear, so try front 1+1/4 and rear 1. If you feel like something goes wrong, go richer with 1/4 increments each time until you fi d a sweet spot.

    Adjusting pilot properly is critical for fuel consumtion as the engine is mainly fed by that circuit (eg highway or city commuting)
    alongat likes this.
  6. Maoule

    Maoule Long timer Supporter

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    I took the SE for a 250 mile ride today. Before riding, I adjusted the flex jets to ~ 2 1/4 and 2 turns then had to turn up the idle a smidge. The motor runs smoother at all throttle inputs, especially at the low end. I am getting more decel popping than before...@Opanos, do you have any suggestions for that. There is also a slight bogging when wacking the throttle at lower rpm (3-4000), but it keeps pulling until the fueling catches up. The crazy thing is, in the middle, it starts pulling really strong, then, about the time you expect it to start leveling off, it keeps pulling harder (my buddy commented on it as well). Unfortunately, in 6th gear it’s well into triple digits and the front Scorpion rally likes to wobble
    The intake noise at highway cruise is definitely there; as I mentioned before, not as noisy as the ITG filter on the 990...I guess I need better earplugs
    The first fill-up after a spirited highway run in the morning, gave me 40.2 mpg on non ethanol premium; the 2nd fill-up I forgot to get the amount of fuel before it was cleared. The last fill-up was after a mix of dirt, gravel and 60-115mph highway, afternoon (93°F and into the wind), 10% ethanol and netted a 37.5 mpg. Overall, not terrible..maybe 1-2mpg less than before.
  7. opanos

    opanos Been here awhile

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    Yes, fuel consumption is higher because your pilot is still rich. You can adjust your ims definitely leaner, and this has great effect on fuel consumption. Try 1 turn less on both cylunders and see what happens. As for the bogging issue, it is probably due to high float level, just try next time to set them to 3mm.

    Also, if you like wacking the throttle from lower rpm, it might be better to switch back to 42 pilots.
  8. alongat

    alongat Fesh Fesh

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    I agree - I’ve had better overall rideability and response with 42 instead of 45
  9. opanos

    opanos Been here awhile

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    unfortunatelly, neither 42 nor 45 is the ''right'' idle jet, and in my point of view this is due to the very lean initial part of the needle (maybe, due to emission requirements, and talking about the stock needle, as it is has a far superior profile than the fp needle)

    42 pilot meters fuel much better in high throttle inputs from low rpm, but has softer throttle response and creates lean overrun condition, if needle is in the correct notch (the 2nd one)
    45 has crisp throttle responce at low rpms and low to medium throttle inputs but is very rich if you WOT in low rpms (afr goes crazy rich)...No lean over run though which if occurs, is super annoying, especially on the highway, so this is why 45 is my weapon of choice and what I personally recommend. Some idle/airjet is always required if you want to get the best out of your cv's, but unfortunatelly, I dont remember my config....
  10. Bearded Hooligan

    Bearded Hooligan Moto Addict

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    I installed my kit this weekend and based my jetting on other local SE’s with open air filters. Those recs were spot on. I am nearly at sea level, about 100 feet.

    Front Carb
    45
    172
    2.5 turns out on the Flex Jet

    Rear Carb
    45
    175
    2.5 turns out on the Flex Jet

    Started up easily, pulls harder in all gears and now revs much quicker than before. I have not noticed any flat spots yet. Only have about 35 miles on it so far of mixed riding. Intake sounds nice, but not annoying, slightly noisier than stock. All over definitely has more seat of the pants power, noticeably in the mid and upper RPMs. I love that I can access it for service with no tools and this is with the Safari tank in place. Happy I waited for this kit over the others on the market.

    Thanks @alongat
    syky27, alongat and nk14zp like this.
  11. bobone

    bobone Been here awhile

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    if your experiemtnation hit 3dprinted pa12 hit me up
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  12. Rassilon

    Rassilon Adventurer

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    awesome! will be placing an order soon for my 990ADV :D
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  13. alongat

    alongat Fesh Fesh

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    Thank you for the support and patience.

    What float height did you set?
  14. Bearded Hooligan

    Bearded Hooligan Moto Addict

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    I left the floats where they were, dont have a #, and I left the needles where they were, also dont have a #. I figured to change as little as possible in the event that something went wrong I’d have less to troubleshoot. If it was close I knew I’d need to make changes to either the float or the clip on the needle.

    Thanks again @alongat for a great product. Very happy with how my SE turned out.
    alongat likes this.
  15. Olmatey

    Olmatey Been here awhile

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    would you suggest this setting for up around 1000m alltidude?
  16. opanos

    opanos Been here awhile

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    It wont be bad for sure, i have been in that kind of altitude with no issues for sure.

    In your case, maybe some butt dyno tuning would be the best bet. Start with 170/175 and try one or two size reduction per cylinder each time. Maybe 42 pilots would be a good idea for higher altitudes
    Olmatey likes this.
  17. Rassilon

    Rassilon Adventurer

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    Do the RC8 short velocity stacks work with the Tripleclamp intake? Recommended or no? any thoughts?
    Was gonna grab the Rottweiler dogbox to go with this, and they have those for pretty cheap...
  18. alongat

    alongat Fesh Fesh

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    RC8 velocity stacks do work with the 990s...@keener runs them but we haven’t observed any performance advantage with them apart from the very top end (as you’d expect from shorter stacks) and they’re super cheap from Ktm... As for the doghouse, it fits no problem.
  19. nk14zp

    nk14zp Long timer

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    Have you ridden long enough to see what your mpg is now?
  20. Bearded Hooligan

    Bearded Hooligan Moto Addict

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    Not yet. Only done about 30 miles and only dumped a small amount in the tank since I plan on flushing the coolant this weekend. Didn’t want to deal with a full Safari tank.
    nk14zp likes this.