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Thread: 2016 300exc carb question

  1. #21
    King Moto
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    Aye.... most of the terrain here is in the sea level to first incitement stage here (unless you go to Mussandam/Fujairah, then you go up an elevation) so with the air density vs UK temperature range, its very close in terms of base jetting. That was my reference point.

    The two aren't that far apart.... but there's a pinch point I couldn't nail with the 200 including the loading up for sand running, which I eventually solved with some tweaks, silicone sealing the worn exhaust flange and repacking the exhaust. Nice and crisp now.

    It's not my thread though..... I'm just trying to help.


    Sent from my iPhone using Tapatalk

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  3. #22
    Adult Moto
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    Ok I will try the N8RH and feedback what I find, where are you guys getting the information about needles, IE richer/ leaner. I can't find a good site.
    Cheers for the help
    Andy
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  4. #23
    The "Moto" steveman's Avatar
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    Quote Originally Posted by ktm450awyeah View Post
    He only thinks it's rich it isn't
    How can you know?

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  6. #24
    The "Moto" Pindie's Avatar
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    Quote Originally Posted by tetley View Post
    If going from an N8RG to a N8RH doesn't clean it up enough, then an N8RW will lean it more, or a N8RJ leaner still. But this is only in the 0 - 1/8 throttle zone where the needle is actually straight not tapered. (which is where you want to make changes)
    The '8R' is the needles' tapers, and all of the above are the same, although they may have to be on a different clip to get the same 1/8 - 3/4 throttle response.

    The NECJ works well on these and a lot of other engines as it is very lean at 0- 1/8 throttle (J) and has a very fat first taper from 1/8 - 1/2 throttle. This makes the bike very smooth for slow technical stuff, trail riding and tarmac cruising. A trade off is a little less power and snap lower down, but I keep my MJ rich at 172 - 175, so full power is available at WOT. As most riding is done at low throttle, this set up gives superb fuel range, 105 - 110 miles a tank on a trail ride! Bit less on an enduro of MX tack day.

    Ps, 'N' is just the series of Keihin needles, so irrelevant to tuning
    I used the NECJ on my 200, it was great and very linear and clean but it needed more punch as you just open the throttle so went to an NEDJ - this needle is slightly richer in the straight section and transforms things. I'm running it in clip 4 and find I have to tweak the air screw (38 pilot) to suit as the normal settings like 1.5 turns out might be right in what's written in a book but on the hill I get a burble so tweak the AS till the burble goes: result = clean idle, crisp throttle, not burble, good torque once getting onto the taper from the straight section. Getting each region of your jetting overlapping nicely is not easy at first but once you do it does not take long to identify which way to go at region of the throttle.
    This is all I can see when I open the throttle:

    Before https://www.youtube.com/watch?v=UWMWXJvX8e4

    After https://youtu.be/VtBLqkh5u8k

    Keep out the way!

  7. #25
    The "Moto" shipdamite's Avatar
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    NECJ # 3 / 40 / 168 all year round on a 2014 300 exc. just changed reeds at 150 hrs, but that was only due to grit after a bog sinking. a repack of the exhaust makes a lot of difference to performance as well.
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  8. #26
    The "Moto" ktm450awyeah's Avatar
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    Quote Originally Posted by steveman View Post
    How can you know?
    I've rode with that needle for 2 years or more
    82 Rm 125 83 Rm 250 84 Cr 500 88 Rm 250 89 Cr 250 91 Cr 250 98 kx 250 99 kx 250 2000 Cr 250 2001 Yz 250 2002 ktm 200 2003 ktm 200 2004 ktm 450 2006 ktm 450 2008 ktm 450 2009 husaberg Fi 450 2013 husaberg 300 now N8RH needle clip 2 with .2mm shim 168 main 38 pilot AS 1.5 turns out[ 2015 ktm 300 N8RG needle clip 2 38 pilot 170 main AS 1.75 out 2016 300 N8RG needle clip 2 40 pilot 170 main AS 1.75 out
    [2017 300 needle 43-74. Clip 2 .1shim pilot 45 main 460 crisp and sweet[

  9. #27
    The "Moto" Pindie's Avatar
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    Ships right. If it's crackly or harsh sounding you need a repack. Poom, poom, poom not dang, dang dang from the silencer.

    Only costs £5 to do so do it if you don't know when last changed.
    shipdamite likes this.
    This is all I can see when I open the throttle:

    Before https://www.youtube.com/watch?v=UWMWXJvX8e4

    After https://youtu.be/VtBLqkh5u8k

    Keep out the way!

  10. #28
    King Moto tetley's Avatar
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    Of course this thread leads on to the question of what is the definition of lean or rich? Very subjective.
    KTM jetting chart is 'correct' for certain conditions, but as most find, it's way too rich. This is fine for fast aggressive riders that need maximum torque and snap out of corners, and ride on the pipe and brakes all the time. The rich bottom end also allows for cold Le-Mans race starts without choke, and gives maximum engine braking due to a lack of firing on the overrun.
    Most riders don't ride at expert and pro levels, so find the chart jetting completely wrong for slower riding, especially for trialsy technical stuff, trail riding and tarmac cruising.
    These engines have more than enough power, so loosing a little bottom end traded for a smooth response is a good deal, as I said above, I keep my MJ rich according to the chart jetting, so if I want full power, it's there at WOT.
    steveman likes this.

  11. #29
    The "Moto" steveman's Avatar
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    Quote Originally Posted by ktm450awyeah View Post
    I've rode with that needle for 2 years or more
    Mh... I used it too, my experience is contrary. The N8R-G is very rich and putting it in clip #1 is not a good idea to get rid of the low down over richness.

    As I had the same problems as the TO I know that the pre 2017 models of the 300 had a low down blubber when jetted as per KTM recommendation. Not only mine, all of them.

    I cant remember the exact data but know it was N8R-G clip, #3 and 35PJ. Dunno the MJ but guess it was 175 or a tad leaner. After many e-mail conversations and some phone calls at JD I can assure you, that none of the 300's jetted according to KTM recommendations ever had a lean stutter down low. Exactly that is the reason why the JD needles work so well at small throttle openings. In combination with the smaller MJ's they make the bikes very lean down low, too lean for many fast riders...

  12. #30
    The "Moto" shipdamite's Avatar
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    Steve

    my experience with the 2014 JD jetting kit - which is basically the needle - was not good. I emailed JD and told him that the kit (which as it turned out was for a 2013 as they hadnt actually made one for the 2014 at that stage) was not as I had expected ... he kindly sent me 5 needles for 'evaluation' ... this was at the same time that the NECJ came along ..... NONE of the JD needles worked as well as the NECJ ..... I emailed him and advised him of my findings and I didnt hear anything back from him

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