Keihin on 2018 ktm recommendations

I have an 18 250xc and have the mikuni running good with the jd kit. However I came across a 38mm keihin pwk airstriker for a great price and grabbed it. It came with a #7 slide and n1eh and necj Suzuki needle. I know plenty have gone to the keihin on the 17/18 bikes but in my searching I haven't found anyone's settings. I may leave the mikuni for the winter if no one has a good starting point. I'm in Ohio around 1200 feet and I'd like to have a setting for winter and a setting for summer. Today was around 20 degrees Fahrenheit. Any help would be much appreciated.

 

In the meantime I also plan to ask jd if they'd swap out the mikuni kit for a 38 keihin kit. I don't know if they will or not..

 

Thanks in advance

'17 300 XC Current setup

  • Reeds:  VForce 4
  • Head:  Stock
  • Exhaust:  Stock
  • Silencer:  Stock
  • Carb:  PWK 38 AG (stock for 2016 150 SX)
  • Altitude:  700' - 1400'
  • Temp:  70 - 85
  • Pilot:  42
  • AS:  1.5
  • Slide:  7.0 (came in the carb)
  • Needle:  NECH, 3rd
  • Main:  168 (still need to verify, but 170 was too rich)
  • No Power Valve adjustments yet, want jetting done first
'17 300 XC Current setup
  • Reeds:  VForce 4
  • Head:  Stock
  • Exhaust:  Stock
  • Silencer:  Stock
  • Carb:  PWK 38 AG (stock for 2016 150 SX)
  • Altitude:  700' - 1400'
  • Temp:  70 - 85
  • Pilot:  42
  • AS:  1.5
  • Slide:  7.0 (came in the carb)
  • Needle:  NECH, 3rd
  • Main:  168 (still need to verify, but 170 was too rich)
  • No Power Valve adjustments yet, want jetting done first


Thanks. A 45 pilot and 165 main came in it. I've been told that the 250 requires richer jetting than the 300. So with your main being 168 at 70-85 maybe I should be around 175-180 for the main..I suppose I could try the 45 pilot to see if it's close since you're at 42. Any idea if the nech is close to the necj? I hope to use that needle because I have heard so many like it on the ktm 2 strokes.
2 minutes ago, yzrider383 said:

Thanks. A 45 pilot and 165 main came in it. I've been told that the 250 requires richer jetting than the 300. So with your main being 168 at 70-85 maybe I should be around 175-180 for the main..I suppose I could try the 45 pilot to see if it's close since you're at 42. Any idea if the nech is close to the necj? I hope to use that needle because I have heard so many like it on the ktm 2 strokes.

 

NECJ is two steps leaner on the straight section (diameter).  From around 1/4 on up it's the same.

NeedleEffect.jpg&key=00bc159f706dd2b6db5

NECJ is two steps leaner on the straight section (diameter).  From around 1/4 on up it's the same.
NeedleEffect.jpg


Thanks again. I think that would equate to needing a larger pilot than the nech but not much else.
At the moment I thinking 45p, necj-3, 175 main. But it's 25°f and below so maybe even need 4th clip

38 is large for a 250. I would have used a 36

I have a 17 250 SX, with a 38 PWK Keihin set up like this at 200ft to 1000ft

Main 168

Pilot 40

Necj 3rd

AS 1.5 turns

Runs ok, but haven't really flogged the bike lately, too much rain to go fast. 

However starting the bike for me is much easier, it was fairly often I had to lean the bike over and get the mikuni to overflow, and give it tiny bit of gas with the choke on. Now it 1 kicks over every time with the choke.

14 hours ago, bowser said:

38 is large for a 250. I would have used a 36

I used a 38 for motocross, but a 36 is supposed to give better low end. But its still leaps and bounds better than the mikuni.

'17 300 XC Current setup
  • Reeds:  VForce 4
  • Head:  Stock
  • Exhaust:  Stock
  • Silencer:  Stock
  • Carb:  PWK 38 AG (stock for 2016 150 SX)
  • Altitude:  700' - 1400'
  • Temp:  70 - 85
  • Pilot:  42
  • AS:  1.5
  • Slide:  7.0 (came in the carb)
  • Needle:  NECH, 3rd
  • Main:  168 (still need to verify, but 170 was too rich)
  • No Power Valve adjustments yet, want jetting done first

Hmmmm, the JDJetting instructions have me at 175 and 45 for 3,000 - 6,000 :-O
4 minutes ago, KennyMc said:

Hmmmm, the JDJetting instructions have me at 175 and 45 for 3,000 - 6,000 :-O

Compare that JD needle to an NExx needle and you'll notice a pretty drastic difference in the tip diameter.

Edited by redrider144

A necj and a #7 slide will be lean,unless you are at altitude and hot temps.

2 strokes don’t like lean.

Edited by E-TECH
2 minutes ago, E-TECH said:

A necj and a #7 slide will be lean,unless you are at altitude and hot temps.

2 strokes don’t like lean.

The J is only leaner up to 1/4 throttle compared to the H I'm running.  He might be able to go richer on the pilot and be ok.

He just has to keep that in mind that since he's around 1200 ft that he may end up wanting an H if he can't get it to run clean 0 to 1/4 throttle and still idle ok with the J.

Thanks for the replies. I got the 16 throttle assembly, cable and carb on last night. I put it in with a 45 pilot, necj-3 and a 175 main. I went what I would think would be plenty rich and will prob work my way down as needed. I was really surprised when the bike started first kick and idled? It revs clean but my garage is much warmer than the 20 degree temps outside. I hope to take it out today a bit just to get a feel for the current settings. In the garage the pilot was definitely rich. I'm at 1336 feet accoridnt to my phone. Some of you feel the necj may not work well for me?

The J is only leaner up to 1/4 throttle compared to the H I'm running.  He might be able to go richer on the pilot and be ok.
He just has to keep that in mind that since he's around 1200 ft that he may end up wanting an H if he can't get it to run clean 0 to 1/4 throttle and still idle ok with the J.



I really appreciate your constructive advice sir. I could order the nech if it seems that'll be the way to go. I'll just ignore the posts that don't add a dang thing to the conversation. I live beside a ktm dealer and he's a friend if mine. He did say he's had many guys use the necj but also knows that I'm pickier than alot of those guys. So I'm again appreciate the help.

If the nech is richer than the necj in the 1/8-1/4 throttle, it will make the low end a little less responsive. It being lean makes it wake up fast.

I have a 17 250 SX, with a 38 PWK Keihin set up like this at 200ft to 1000ft
Main 168
Pilot 40
Necj 3rd
AS 1.5 turns
Runs ok, but haven't really flogged the bike lately, too much rain to go fast. 
However starting the bike for me is much easier, it was fairly often I had to lean the bike over and get the mikuni to overflow, and give it tiny bit of gas with the choke on. Now it 1 kicks over every time with the choke.
I used a 38 for motocross, but a 36 is supposed to give better low end. But its still leaps and bounds better than the mikuni.


Thanks for the input sir. I agree even when I had the mikuni jetted well it still took many kicks cold and often had to be leaned over. This carb immediately started up and idled. I would appreciate an update as you ride more. Our altitudes are not far off at the top of your range.

I rode yesterday, it was 45F out and had a bunch of moisture in the air. Been raining the previous couple of days. Bike started up 1 kick with the choke. Idled pretty good. I rode around, bike revved up really nice and clean. I did some Motocross starts, it ran really good and didnt do anything strange. However after cruising at 1/2 throttle and coming to a stop, the bike sat there with a elevated idle then it died back down to a normal set idle.

I rode yesterday, it was 45F out and had a bunch of moisture in the air. Been raining the previous couple of days. Bike started up 1 kick with the choke. Idled pretty good. I rode around, bike revved up really nice and clean. I did some Motocross starts, it ran really good and didnt do anything strange. However after cruising at 1/2 throttle and coming to a stop, the bike sat there with a elevated idle then it died back down to a normal set idle.


Hmm okay. That helps too. That would mean it would benefit from a larger pilot I believe, because its needing more fuel at closed to bring the idle back down. I'm going out to play a bit just to see where mines at.

Ok after playing in the back field a bit..it starts one kick and idles good. I got it operating temp and it's way more responsive than the mikuni ever was that's for sure. I did a couple wide open pull and it definitely pulls hard. I do have some spooge but not terrible. However if I'm real low throttle and and try to crack it open out of a turn it'll bog real quick then come on strong. I was also able to repeat at idle once I stopped. If idling or atleast low rpm coming down from a rev if I crack it open it'll bog. Would trying clip 4 on the needle resolve this?

I think so, I actually think I am sitting at 3.5 clip pos on the needle. I used the spacer that I got with the mikuni jd jet kit. I think thats what is helping me right now, however the dirt at my house doesnt have a bunch of traction at the moment, so there isnt a huge load on the engine.

1 hour ago, Lahms said:

I rode yesterday, it was 45F out and had a bunch of moisture in the air. Been raining the previous couple of days. Bike started up 1 kick with the choke. Idled pretty good. I rode around, bike revved up really nice and clean. I did some Motocross starts, it ran really good and didnt do anything strange. However after cruising at 1/2 throttle and coming to a stop, the bike sat there with a elevated idle then it died back down to a normal set idle.

Go to richer NEDH.  you will se why as soon as you ride it.

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