125/150/250/300 KTM/HUS/GG jetting thread

sandman768 wrote:

Hey guys, I am about to order the needed carb parts to try this jetting, regarding the 42-74 needle… does it have to be a Yamaha...

Hey guys, I am about to order the needed carb parts to try this jetting, regarding the 42-74 needle… does it have to be a Yamaha needle or is the Ktm 42-74 needle the same? Thanks

AJ565 wrote:

Same

sandman768 wrote:

Thanks AJ565, I don’t even have the bike yet, 2022 125SX, but I know with proper jetting the Mikuni can work very good. My 2018 250SX...

Thanks AJ565, I don’t even have the bike yet, 2022 125SX, but I know with proper jetting the Mikuni can work very good. My 2018 250SX is jetted properly and pulls 450”s up Southwicks”s deep sand start straight…. curious to see if the stock 125 2022 jetting comes with S4 nozzle, as some people state. I will pull the carb off when I get the bike & post the stock jetting as reference for this awesome thread.

sandman768 wrote:

Hey guys, I am about to order the needed carb parts to try this jetting, regarding the 42-74 needle… does it have to be a Yamaha...

Hey guys, I am about to order the needed carb parts to try this jetting, regarding the 42-74 needle… does it have to be a Yamaha needle or is the Ktm 42-74 needle the same? Thanks

digger wrote:

The KTM and Yamaha 42-74 needles are the exact same. The only reason I listed the Yamaha part# is because it’s a couple of bucks cheaper...

The KTM and Yamaha 42-74 needles are the exact same. The only reason I listed the Yamaha part# is because it’s a couple of bucks cheaper than the KTM part#. It may possibly be easier to get from Yamaha. I was just giving people options.

sandman768 wrote:

Hey guys, I am about to order the needed carb parts to try this jetting, regarding the 42-74 needle… does it have to be a Yamaha...

Hey guys, I am about to order the needed carb parts to try this jetting, regarding the 42-74 needle… does it have to be a Yamaha needle or is the Ktm 42-74 needle the same? Thanks

AJ565 wrote:

Same

sandman768 wrote:

Thanks AJ565, I don’t even have the bike yet, 2022 125SX, but I know with proper jetting the Mikuni can work very good. My 2018 250SX...

Thanks AJ565, I don’t even have the bike yet, 2022 125SX, but I know with proper jetting the Mikuni can work very good. My 2018 250SX is jetted properly and pulls 450”s up Southwicks”s deep sand start straight…. curious to see if the stock 125 2022 jetting comes with S4 nozzle, as some people state. I will pull the carb off when I get the bike & post the stock jetting as reference for this awesome thread.

opyguy wrote:

What do you run for jetting on the 18 250sx? I struggle at southwick on my 250sx, it’s the only track where I feel I was...

What do you run for jetting on the 18 250sx?
I struggle at southwick on my 250sx, it’s the only track where I feel I was much faster on my 350sxf...Leave it in the third and fourth gear and just rev it to the Moon

sandman768 wrote:

Hey guys, I am about to order the needed carb parts to try this jetting, regarding the 42-74 needle… does it have to be a Yamaha...

Hey guys, I am about to order the needed carb parts to try this jetting, regarding the 42-74 needle… does it have to be a Yamaha needle or is the Ktm 42-74 needle the same? Thanks

digger wrote:

The KTM and Yamaha 42-74 needles are the exact same. The only reason I listed the Yamaha part# is because it’s a couple of bucks cheaper...

The KTM and Yamaha 42-74 needles are the exact same. The only reason I listed the Yamaha part# is because it’s a couple of bucks cheaper than the KTM part#. It may possibly be easier to get from Yamaha. I was just giving people options.

sandman768 wrote:

Hey guys, I am about to order the needed carb parts to try this jetting, regarding the 42-74 needle… does it have to be a Yamaha...

Hey guys, I am about to order the needed carb parts to try this jetting, regarding the 42-74 needle… does it have to be a Yamaha needle or is the Ktm 42-74 needle the same? Thanks

digger wrote:

The KTM and Yamaha 42-74 needles are the exact same. The only reason I listed the Yamaha part# is because it’s a couple of bucks cheaper...

The KTM and Yamaha 42-74 needles are the exact same. The only reason I listed the Yamaha part# is because it’s a couple of bucks cheaper than the KTM part#. It may possibly be easier to get from Yamaha. I was just giving people options.

fredmotokx wrote:

Was actually cheaper and easier to get the KTM version out here in Canada, ordered from my local KTM dealer took 2 days for them to...

Was actually cheaper and easier to get the KTM version out here in Canada, ordered from my local KTM dealer took 2 days for them to get it.

What is the setup for power valve adjustment you are using (150sx)? Stock spring 1.75 out from full?

sandman768 wrote:

460 main 37.5 pilot 5.75 slide, stock needle on 3rd clip Stock gearing 50 rear Dunlop mx11 or 12, the newer sand rear tire 50/50 110...

460 main
37.5 pilot
5.75 slide, stock needle on 3rd clip
Stock gearing 50 rear
Dunlop mx11 or 12, the newer sand rear tire
50/50 110 Sunoco unleaded & 91 non ethanol mixed at 40:1 with Amsoil dominator.
I never have tried the S4 nozzle or needle this thread recommends, as I feel it runs really good. If I go to a hard pack or intermediate track I can run a 450 main.
I also have FMF fatty & standard powercore silencer, The bike has great top end & over rev…

sandman768 wrote:

Hey guys, I am about to order the needed carb parts to try this jetting, regarding the 42-74 needle… does it have to be a Yamaha...

Hey guys, I am about to order the needed carb parts to try this jetting, regarding the 42-74 needle… does it have to be a Yamaha needle or is the Ktm 42-74 needle the same? Thanks

AJ565 wrote:

Same

alien wrote:

I broke down and ordered the stock 2016 keihin carb for my 2020 150sx. It comes with the 125 jetting specs even if you order off...

I broke down and ordered the stock 2016 keihin carb for my 2020 150sx. It comes with the 125 jetting specs even if you order off the 150sx engine page. I tried it that way at first and it ran pretty good. I changed the needle and pilot to lean it out and now it rips. The mikuni was great when it was jetted right but it was inconsistent from week to week even with all the suggested setup tips and new jet block. The keihin just runs consistent week to week ,air screw adj. only.
The jetting specs. listed in this thread are very good for the mikuni. They are what I used with the stock carb.

AJ565 wrote:

Same

DuroTools wrote:

AJ or anyone know if you buy the stock 2016 keihin carb from ktm does it come with the jets? The jd one that comes with...

AJ or anyone know if you buy the stock 2016 keihin carb from ktm does it come with the jets? The jd one that comes with jd jets is backordered till September and I'm having a strange issue with my bike that when you tilt it , it will start to die on you. It only happens maybe 50% of the time and I have tried jetting and float height changes in both directions drastically and nothing helps. If I run it super rich it does help but still happens and I've actually stalled at super high rpms just as I lean the bike into a turn and I feel it's potentially dangerous so I'm gonna go with a keihin and try that. If it comes with decent stock settings I'll probably buy it but if I need to get a needle and a bunch of jets I'll probably wait. I do have tons of fcr pilots and mains so if those fit I might just need the needle?

AJ565 wrote:

No idea, but if you’re running a 5.75 slide and a 460 main on a 125 that bike is on the super lean side and maybe...

No idea, but if you’re running a 5.75 slide and a 460 main on a 125 that bike is on the super lean side and maybe part of your problem.

Bruce372 wrote:

Word of caution on the 2016 keihin oem carb, it comes with a 7 slide, unlike the JD aftermarket keihin comes with a 6.5 slide. If...

Word of caution on the 2016 keihin oem carb, it comes with a 7 slide, unlike the JD aftermarket keihin comes with a 6.5 slide.

If you are considering doing a stic down the line, that 7 slide was too lean. Took me ages to figure out and only when Stic sent me one of their carbs did I find out what's up.

Try George at stic, he might have keihins in stock ready to go

Bruce372 wrote:

Tru aomc this weekend, they will probably have a discount going

MYOWNMAN wrote:

Hey guys.. I was hoping someone could help me out? I made all the suggested changes on page 1 to my 2020 250sx, including the JD...

Hey guys.. I was hoping someone could help me out? I made all the suggested changes on page 1 to my 2020 250sx, including the JD gasket kit.

MJ 490
PJ 32.5
AS 1.5 turns out (mine seems to run better at 2-2.5 turns out)
Needle jet S4 (KTM part #55431021400) stock is S1
Needle 42-75 on the 2nd clip (Yamaha part #284-14116-H5-00)
Slide 5.5 (Kawasaki part 16025-0002)
PV 1.75 turns in from all the way out
Fuel mix 50:1. (Amsoil Dominator)
90-93 degrees.
Sea level (texas)

The bike wants to fall flat at 3/4 to full throttle.. it doesn’t sound like it’s on the pipe and it quits pulling.. I’ve also noticed it likes the air screw out to around 2.25-2.5 turns. Also the choke has little affect for starting. I was out at 3 palms today and pulled the choke while rolling the track, it killed the bike shortly afterwards. I feel like I’m a little rich on the pilot, but I can’t tell if I I’m rich or lean up top..I am getting some spooge out of the pipe. Thanks!

MYOWNMAN wrote:

Hey guys.. I was hoping someone could help me out? I made all the suggested changes on page 1 to my 2020 250sx, including the JD...

Hey guys.. I was hoping someone could help me out? I made all the suggested changes on page 1 to my 2020 250sx, including the JD gasket kit.

MJ 490
PJ 32.5
AS 1.5 turns out (mine seems to run better at 2-2.5 turns out)
Needle jet S4 (KTM part #55431021400) stock is S1
Needle 42-75 on the 2nd clip (Yamaha part #284-14116-H5-00)
Slide 5.5 (Kawasaki part 16025-0002)
PV 1.75 turns in from all the way out
Fuel mix 50:1. (Amsoil Dominator)
90-93 degrees.
Sea level (texas)

The bike wants to fall flat at 3/4 to full throttle.. it doesn’t sound like it’s on the pipe and it quits pulling.. I’ve also noticed it likes the air screw out to around 2.25-2.5 turns. Also the choke has little affect for starting. I was out at 3 palms today and pulled the choke while rolling the track, it killed the bike shortly afterwards. I feel like I’m a little rich on the pilot, but I can’t tell if I I’m rich or lean up top..I am getting some spooge out of the pipe. Thanks!

sandman768 wrote:

I would say you are too rich on the main jet, I have an 18 250, I run a 460 & 450 main, I tried larger...

I would say you are too rich on the main jet, I have an 18 250, I run a 460 & 450 main, I tried larger mains, does not like anything above 460 unless it’s super cold out. Very easy to change the main, I would drop 1 size main at a time & try it out. My needle clip position is 3rd, tried 2nd, did not work for me, but I still have stock needle & nozzle for the 18

AJ565 wrote:

Strongly disagree. I’ve ridden 3P many times with the exact jetting I have laid out in the thread. I run a 500 main jet all year...

Strongly disagree. I’ve ridden 3P many times with the exact jetting I have laid out in the thread. I run a 500 main jet all year long. With this jetting anything less then a 490 kills the top end. Actually a 490 is too small for that track(s). He’d be wayyyy too lean with that small of main with the slide change.

MYOWNMAN, are you headed to 3P next weekend? I was going to go this last weekend, but they called for rain so I went to Murphy’s and then it didn’t rain. If I go this Sunday we can need up and get it dialed. You can also spin a few laps on my bike so see how it differs from the 5.5 slide and a 490 to a 5.75 and a 500 setup.

sandman768 wrote:

I would say you are too rich on the main jet, I have an 18 250, I run a 460 & 450 main, I tried larger...

I would say you are too rich on the main jet, I have an 18 250, I run a 460 & 450 main, I tried larger mains, does not like anything above 460 unless it’s super cold out. Very easy to change the main, I would drop 1 size main at a time & try it out. My needle clip position is 3rd, tried 2nd, did not work for me, but I still have stock needle & nozzle for the 18

AJ565 wrote:

Strongly disagree. I’ve ridden 3P many times with the exact jetting I have laid out in the thread. I run a 500 main jet all year...

Strongly disagree. I’ve ridden 3P many times with the exact jetting I have laid out in the thread. I run a 500 main jet all year long. With this jetting anything less then a 490 kills the top end. Actually a 490 is too small for that track(s). He’d be wayyyy too lean with that small of main with the slide change.

MYOWNMAN, are you headed to 3P next weekend? I was going to go this last weekend, but they called for rain so I went to Murphy’s and then it didn’t rain. If I go this Sunday we can need up and get it dialed. You can also spin a few laps on my bike so see how it differs from the 5.5 slide and a 490 to a 5.75 and a 500 setup.