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wich powervalve spring ?
Digger,
I was trying to find the post about the notch in the slide. I have a 2018 and a 2019 ktm 150 sx that I am preparing to file the slides notchs. What depth do I go to?
I am currently running
Slide #5
Main 490
Pilot 30- had a 35 but it was too rich and I have 32.5 and 27.5 coming to try
needle- 42-74
JD gasket
Bike runs better with these settings but want to clean up the idle.
Ricky, I use a 5/32 or 4mm chainsaw file, and file down about 3mm in depth. It's not super critical, like filing the other side of the slide is. There is a pic on page 5 in this thread of a slide that I cut and notched that will give you and idea of what I'm doing, and how deep to go with the notch.
Hi guys, I’m back with your jetting.I don't have the needle so I imagine it should still work better with it.. actually the bike works well even with the wrong needle (currently 44-75 2nd clip). I order and install the right needle and go. I found a needle chart (in French because I'm French 🤪)
The Shop
OK, so it's running good? Yeah 44-75 essentially has grooves cut 1 whole clip richer than 42-75. So, 44-75(2) basically equals 42-75(3). This might not be a bad thing since you're in sand. But, like you said, I would still try 43-75(2) just to be sure and compare.
Hi, I’ve bought a ktm 150 sx 2017 and I’m struggling to get the mikuni carb right. I’ve changed the jet block gasket from JD.
I’ve ordered all the parts in your suggested carb settings for the 17+ 150 hoping to solve the bike it bogs in 1st & 2nd as if it colds when it’s not then picks up. It’s not running crisp like a two stroke should it’s not screaming like a 150 should.
pump gas 98 @ 40:1 2t motorex oil
UK
2022 125SX
MJ 540
PJ 32.5
AS 1.50
slide 5.0 from JD Jetting
Needle 42-74 on the 3rd clip (Yamaha 284-14116-H4-00)
Needle jet S4 (KTM part #55431021400)
PV 1.5 turns in from all the way out.
Fuel mix 91pump/U4.4 2:1 Motorex 36:1
Warning the bike will run very fast on this jet and fuel mix but will run hot. just cracked a head today at ACP. both the piston top and plug were chalk white. very lean. I had an exhaust o ring fail also that may have pushed the lean condition.
after the rebuild im considering
MJ 540
PJ 35
AS 1.0
slide 5.0 from JD Jetting
Needle 42-74 on the 4th clip (Yamaha 284-14116-H4-00)
Needle jet S4 (KTM part #55431021400)
PV 1.5 turns in from all the way out.
Fuel mix 91pump/U4.4 2:1 Motorex 36:1
is there another needle jet that can open the fuel up 5%, maybe the stock S1. Am i correct in thinking the needle jet will affect my main jet. Im up to a 540 from the stock 500 and its still lean. I think there is one bigger main jet i can get, but is there diminishing returns on the bigger jets. the bike too rich with this fuel mix stock and too lean now. I just need a little more fuel.
The S1 is leaner than the S4. You want the S7 to make it richer. Also, on the 2022 bikes I ended up on a 37.5 pilot running AvGas which is non-Oxy. You probably need to go richer on the pilot and/or needle straight section (like to a 42-72 or so) as well. Ultimately you'll need to find the right combo of Needle-jet and Jet-needle to work correctly across the whole range.
Thank you for your input. I have new parts on order and will continue testing.
Hi from Argentina! Ive read the 35 Pages of this Amazing topic. Somebody knows what needle jet ( S1 or S4) comes in 2017 150sx from factory and where is located in carb ? .
Planing go with this
Sea level , between 50°F and 77°F most of the year. running Pump gas. Shell Vpower.
Begginer 180lbs without gear.
(40/50°F Winter sand/dunes conditions)*
MJ 500 (540)*
PJ 35 (37.5)*
Slide #5 JD jetting without notch
S4
Needle 42-74 2 pos (3 pos) *
I hope You can confirm if im in the right direction with this. Thank You all, for be SO active in this topic.
That sounds like some good starting points for you.
Make sure you check the float height also to 8 - 9mm.
From the manual, your bike has the S-1:
To Remove the needle-Jet, remove slide assembly, remove carb from bike, remove float bowl and float, remove main jet, and then remove the 8mm brass nut under main jet (Main jet holder). The needle-Jet is behind that. If it does not fall out the bottom easy, use a tool and push down gently from the top of the carb and it should fall out.
When you have all this apart, you should remove the 2-torx screws and replace the jet block gasket also to make sure that is fresh and sealed well.
https://jdjetting.com/product/jdmk05-mikuni-tmx-jet-block-kit/
Hi,
Tried to find information in this huge thread but think I came up short. I have a Husky TC 125 2020 that is now equipped with KTM complete new 150 kit. The call it factory but I believe it is bog standard 150SX kit or?
Now my real question, the former owner had the TMX38 carb bored out so now I measured it to 40mm, how does this affect jetting? Bike is really bad on low to maybe’s mid throttle with 4.0 slide and jetting according 150 manual. I would say uneven and sputters.
Live in sweden so spring for us now is 40-50F, sea lvl. Have JD gasket. Float looks ok at 60 degrees. Just got a 5.0 slide installed. Have standard needles/jets and JD kit needles/jets for 125. Do not know if the are the same in JD 150 kit. To make matters even worse I will run it mostly on sand MX tracks but I’m only dreaming of wide open, it does not happen in real life. So any jetting advice would be much appreciated.
/Robert
Yeah, still struggling so I will answer myself
Tried to file down my 4.0 slide to a leaner but it looks more like a 5.0 so far. Still used it last time and here are my findings. Rather cold around 9 degrees Celsius cooling down towards 6c later on. Riding rather heavy sand mx-track. Started with 520/35 and 42-71 on 3rd. Sounds and goes like a lawnmower down low
thought it went better when adjusting airscrew out 1 1/2 turn so went down to a 30 pilot and put airscrew back at 1 2/3.
Didn’t really notice any improvement so moved clip up to second. Maybe a slight improvement but still rather bad when trying to maintain a steady (low) trottle. Should I continue moving to first clip or find a leaner needle? A bit unsure to make it leaner since since riding sand and cold temperatures? Could my drilled out carb (40mm) cause me all this headache?
Time for the ole DIY larger slide notch.
My motor was full of oil where the connection pipe/silencer and this is my spark with just two hrs
any advice please 🙏🏼
Tell us what fuel, oil, and ratio you are using and also what jetting is in the carb now.
Fuel 91 Motorex oil 40:1 tomorrow I will open the carb and I will let you know wat jetting 🙏🏼🙏🏼
Hello so it is what I have so far
Pit Row
I can’t read any numbers on the needle
The needle number will be stamped here.. use the zoom function on your phone to read it...
In the meantime, I will say that you'll likely be much better off by simply raising the needle clip 1 or 2 positions. You're currently in the 2nd richest position there which is likely excessive for 4500ft, especially if the temperature is also warm.
Thanks a lot I will do it and I did try to read with the phone on the needle but there is nothing stamped, I do have another needle number 6BFY44-73 the previous owner gave it to me should I use it?..and I also did some research and I see people using PJ 40 instead than 42..what you think?
Thanks again for the help
The 6BFY44-73 is a Mikuni needle. Won't work in your Keihin.
For now I would try moving the clip up 1 position. 1 change at a time or else you might get yourself lost with changes.
Yes, in other pages they recommend at least, 35 PJ if You don't notch the slide . 32.5 if You notched the slide .also you can try running 40:1 premix. Check float level heigth.
I actually found this online for Keihin carb..what do you think?
If that is the NOZI needle you have, it may be somewhat useful. Also, assuming you have the same size slide that the 150 came with when it had the Keihin that chart is for. That shows clip#2 for your elevation and mid-temps so I'd try 3 and then 2 and see what it gives you.
Post a reply to: 125/150/250/300 KTM/HUS/GG jetting thread