ktm 300 sx jetting

jd864
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jd864
Edited Date/Time 4/6/2016 8:23pm
digger seems to well informed about this. I have 13 250sx that I just put the 300 sx kit. it runs great after 1/4 throttle. I am in so. al. current temps 90/95 deg. 45/55% humidity. running stock jetting for the 250. pv and tdc set as per ktm cd. runs great after 1/4 throttle needle at 4th. tried 40 pj. and ran worse. went back to 42. rechecked x dim and reset it to spec,s. runs better but still 1/6 to 14/ throttle is bad HELP. Jason jd_19602002@yahoo.com
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jd864
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jd864 8/16/2015 1:11pm
8/16/2015 1:11pm
It sputters like it won't run clean. I just spent 4 hr. Testing needles main jets and clip post. The best was a 160 main 40 idle jet and no eh needle in 4 post. Ran alot better but plug was white so that combo is no good. I went front 1 turn to 2 on air screw. No results. I have yet to find jetting for a 13. Most are 2011 or 14. Stock is noei 3rd post. 42 idle and 158 main.
KTMShane699
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KTMShane699 8/16/2015 3:31pm
8/16/2015 3:31pm
Use a Suzuki NECJ needle on the third clip for race gas or fourth for pump. A 175-180 main and a 42-45 pilot. Live happily ever after.

Shane
jd864
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jd864 8/16/2015 5:12pm
8/16/2015 5:12pm
There is a J jet in kit. Not shure what is richer on a main. Higher or lower # s.
jd864
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jd864 8/16/2015 5:13pm
8/16/2015 5:13pm
Ktm book and cd 8s weak in info.

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KTMShane699
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KTMShane699 8/16/2015 5:48pm
8/16/2015 5:48pm
The NECJ needle is a Suzuki needle. It's not like anything in the kit.

Shane
digger
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digger 8/16/2015 7:58pm
8/16/2015 7:58pm Edited Date/Time 8/17/2015 6:35pm
jd864 wrote:
digger seems to well informed about this. I have 13 250sx that I just put the 300 sx kit. it runs great after 1/4 throttle. I...
digger seems to well informed about this. I have 13 250sx that I just put the 300 sx kit. it runs great after 1/4 throttle. I am in so. al. current temps 90/95 deg. 45/55% humidity. running stock jetting for the 250. pv and tdc set as per ktm cd. runs great after 1/4 throttle needle at 4th. tried 40 pj. and ran worse. went back to 42. rechecked x dim and reset it to spec,s. runs better but still 1/6 to 14/ throttle is bad HELP. Jason jd_19602002@yahoo.com
You will never get the bike to run clean with the stock N1EH needle. The 1st taper on those needles is so short that you can often bypass it by over adjusting the idle screw, which puts you into the start of the 2nd taper. Those needles N1Ex and it's 1/2 clip leaner brother NOZx needles were designed to simply have a harder hit into the middle, which may or may not be what some people are looking for.

If you want the bike to run cleaner down low, and have a smoother transition into the middle ? use the needle and jetting specs that Shane mentions. The Suzuki NECJ or the 1/2 clip position richer NEDJ in the #3 clip along with a 42/ or even a 40 pilot for the temps you're riding in along with a 172 main should get you pretty close. If you're looking for a little more hit into the middle, but is still pretty smooth, try a Suzuki N3WK in the #3 with the same pilot and main as the NExx needle.

NECJ=http://www.motosport.com/dirtbike/oem-parts/suzuki/2007/rm250/carbureto…

N3WK=
http://www.motosport.com/dirtbike/oem-parts/suzuki/2000/rm250/carbureto…

jd864
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jd864 8/17/2015 2:13pm
8/17/2015 2:13pm
Thanks guys. I have a necj and 172 coming.
rocketsocks26 8/17/2015 6:31pm
8/17/2015 6:31pm
jd864 wrote:
digger seems to well informed about this. I have 13 250sx that I just put the 300 sx kit. it runs great after 1/4 throttle. I...
digger seems to well informed about this. I have 13 250sx that I just put the 300 sx kit. it runs great after 1/4 throttle. I am in so. al. current temps 90/95 deg. 45/55% humidity. running stock jetting for the 250. pv and tdc set as per ktm cd. runs great after 1/4 throttle needle at 4th. tried 40 pj. and ran worse. went back to 42. rechecked x dim and reset it to spec,s. runs better but still 1/6 to 14/ throttle is bad HELP. Jason jd_19602002@yahoo.com
digger wrote:
You will never get the bike to run clean with the stock N1EH needle. The 1st taper on those needles is so short that you can...
You will never get the bike to run clean with the stock N1EH needle. The 1st taper on those needles is so short that you can often bypass it by over adjusting the idle screw, which puts you into the start of the 2nd taper. Those needles N1Ex and it's 1/2 clip leaner brother NOZx needles were designed to simply have a harder hit into the middle, which may or may not be what some people are looking for.

If you want the bike to run cleaner down low, and have a smoother transition into the middle ? use the needle and jetting specs that Shane mentions. The Suzuki NECJ or the 1/2 clip position richer NEDJ in the #3 clip along with a 42/ or even a 40 pilot for the temps you're riding in along with a 172 main should get you pretty close. If you're looking for a little more hit into the middle, but is still pretty smooth, try a Suzuki N3WK in the #3 with the same pilot and main as the NExx needle.

NECJ=http://www.motosport.com/dirtbike/oem-parts/suzuki/2007/rm250/carbureto…

N3WK=
http://www.motosport.com/dirtbike/oem-parts/suzuki/2000/rm250/carbureto…

I took your advise an put the 7.0 slide in and it works REALLY well! I I also just put the nedj needle in, my bike keeps getting better n better lol smartest thing I did was go back to the smoker
jd864
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jd864 8/18/2015 1:40pm
8/18/2015 1:40pm
I have jets on the way. I will let u know how it works.
kylant
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kylant 8/18/2015 6:28pm
8/18/2015 6:28pm
how about 300 sx jetting with a 38mm carb?
rocketsocks26 8/19/2015 1:31am
8/19/2015 1:31am
kylant wrote:
how about 300 sx jetting with a 38mm carb?
that is with a 38mm
kylant
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kylant 8/19/2015 5:28am
8/19/2015 5:28am
kylant wrote:
how about 300 sx jetting with a 38mm carb?
rocketsocks26 wrote:
that is with a 38mm
i didn’t see any mention of those jetting specs being with a 38mm carb
Digger29
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Digger29 8/19/2015 6:27am
8/19/2015 6:27am
I had 38mm carbs on both of my 300SX's and I ran a 40 pilot and the NECJ needle and a 175 main and they both ran tremendous.
kylant
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kylant 8/19/2015 6:48am
8/19/2015 6:48am Edited Date/Time 8/19/2015 6:49am
Digger29 wrote:
I had 38mm carbs on both of my 300SX's and I ran a 40 pilot and the NECJ needle and a 175 main and they both...
I had 38mm carbs on both of my 300SX's and I ran a 40 pilot and the NECJ needle and a 175 main and they both ran tremendous.
what elevation?
what slide?
KTMShane699
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KTMShane699 8/19/2015 6:50am
8/19/2015 6:50am
kylant wrote:
what elevation?
what slide?
Sea level. And I believe it was a 6.5 slide. It was whatever slide came with the 250. I had the same setup as Digger.

Shane
jd864
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jd864 8/19/2015 4:32pm
8/19/2015 4:32pm
Ok got necj needle 172 main in today. Installed needle 3rd. Post. Air 11/2 out. Unreal freaking real how it cleaned up . 42 pilot jet. Rode about 2 miles. Clean and responsiveness was awsome. All rpm ranges and smooth. 3rd gear wot and shut off. Plug was a little grayish. Going to try a little in on air screw. Maybe the 175 main. I am so happy. Runs better than stock 250 did. Thanks to all those for your help. U guys rock!
jd864
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jd864 8/19/2015 4:35pm
8/19/2015 4:35pm
That's the stock 36mm on 13 250 sx settings.
jd864
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jd864 8/28/2015 3:02pm
8/28/2015 3:02pm
Still a little sputtering off idel. And a little lean at wot. 175 main necj needed 4th post. 42 pilot. On pump gas mix with race. Looking for a 180 main. Hope that works.
gameover
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gameover 4/6/2016 8:23pm
4/6/2016 8:23pm
jd864 wrote:
Ok got necj needle 172 main in today. Installed needle 3rd. Post. Air 11/2 out. Unreal freaking real how it cleaned up . 42 pilot jet...
Ok got necj needle 172 main in today. Installed needle 3rd. Post. Air 11/2 out. Unreal freaking real how it cleaned up . 42 pilot jet. Rode about 2 miles. Clean and responsiveness was awsome. All rpm ranges and smooth. 3rd gear wot and shut off. Plug was a little grayish. Going to try a little in on air screw. Maybe the 175 main. I am so happy. Runs better than stock 250 did. Thanks to all those for your help. U guys rock!
What pre mix oil are you using? And what ratio?

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