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Only $10 for all 2026 SX, MX, and SMX series.
When are the actual bikes hitting the dealerships?
Where did you find the manual? I'm not seeing anything for 2026 models on Yamaha's website.
Rocky Mountain and Motosport have parts breakdown.
Heard August dealers would have the normal 125 model. Anniversary was October.
2025 YZ125 STD Specs
Carburetor: Keihin PWK38S
Main jet: #160 (AUS, NZL, ZAF: #162)
Main air jet: #200
Jet needle: NYDF (AUS, NZL, ZAF: NYCF)
Clip position: #2 (AUS, NZL, ZAF: #3)
Needle jet: 2.9(#6)
Cutaway (Slide): #7
Pilot outlet: 0.8
Pilot jet: #75 (AUS, NZL, ZAF: #62)
Bypass 1: 1.5
Air screw turns out: 2-5/8 (AUS, NZL, ZAF: 1-3/4)
Valve seat size: 3.8
Starter jet 1: #85
Power jet: #35
Float height: 6.5 mm (0.26 in)
Spark plug: NGK/BR9EVX
2025 Yamaha YZ125 Owner's Manual
https://library.ymcapps.net/library/om/contents/pdf/10/D68-28199-50_02.pdf
2026 YZ125 STD Specs NEW
Main jet: #178
Jet needle: N3EW
Clip position: #2
Pilot jet: #65
Air screw turns out: 1-3/8
Power jet: #95
Float height: 5.5 mm (0.22 in)
2026 Yamaha YZ125 Owner's Manual
https://library.ymcapps.net/library/om/contents/pdf/10/D68-28199-51_02.pdf
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If anyone wants to try the 2026 OEM jetting specs keep in mind that the air screw assembly is also updated for 2026.
More information on the updated 2026 YZ125 air screw assembly……
If you have a 2023 through 2026 YZ125X, it comes stock with this air screw. Part # is 4SR-14105-01.
If you have a GYTR Y4 jet kit, it should have this air screw in the jet kit. Part # 4SR-14105-01.
If you have a 2022 through 2025 YZ125, you have the old air screw assembly and will need to get the updated air screw when using the 2026 YZ125 jetting spec.
What is the difference in air screw ? Has anyone tested float height 5.5mm vs 6.5mm?
I did not feel too much difference between 35 and 70 power jets
Also, as mentioned earlier, the 2026 has a new intake and new ignition mapping. The new mapping may also include new opening and closing RPM and throttle positions for the power jet. There's no way of knowing that unless Yamaha would publish something or someone would put the bikes on a dyno with a tach and gather that info. All this is to say, dropping the 2026 jetting in a 2022-2025 bike may not result in a bike that runs exactly like a 2026.
Solid information and thanks for sharing!
I have never been able to find the power jet opening details for the previous year model YZ125’s. For 2026, Yamaha has some of that detail listed in the manual (pictured below).
As of now, the 2026 CDI and Intake boot are not available from RMATV or Motosport.
2025 Yamaha YZ125 Owner's Manual
Some additional changes to supplement the changes to the carburetor settings
YZ125 2022-2024
B4X-11311-00 CYLINDER 1
B4X-85540-00 C.D.I. UNIT ASSY
B4X-82509-00 WIRE, SUB LEAD
B4X-13610-00 REED VALVE ASSY
B4X-13565-00 JOINT, CARBURETOR
1C3-14453-11 JOINT, AIR CLEANER 1
BCR-14401-00 AIR CLEANER CASE ASSY
4SR-14105-00 PILOT SCREW SET
YZ125 2025 changes compared to 2022-2024
B4X-11311-01 CYLINDER 1
B4X-82509-01 WIRE, SUB LEAD
B4X-13610-01 REED VALVE ASSY
YZ125 2026 changes compared to 2025
D68-85540-00 C.D.I. UNIT ASSY
D68-14453-00 JOINT, AIR CLEANER 1
D68-14401-00 AIR CLEANER CASE ASSY
4SR-14105-01 PILOT SCREW SET
So, there you have it. Cool that they actually give the power jet info.
2025 Power jet Open 0-8500rpm and 1/2 to full throttle.
2026 Power jet Open 0-7200rpm and 1/3 to full throttle.
So, yeah, you'd need the newer CDI to get the same Power jet operating parameters as the 2026.
We're here doing all this hypothesis, but we don't even know how the 2026 will run yet! Hopefully it runs great. All the changes they made would seem to give hope since they look pretty intentional and thorough.
Just got a chance to test the 2026 YZ125 OEM jetting spec in my 2024 YZ125X. First impression is great!
Need to test on the track at full operating temperature and load but initially I’m stoked. It runs great!
172 main
65 Pilot
N3EW-2
90 power jet (95 was not in stock)
2.5 out on AS
#7 slide
5.5mm Float Height
80 degree air temp
This is the summer time setting in the 2026 YZ125 manual except for the power jet (90 vs 95).
Just got done with 3 moto’s at the track and the engine runs clean from bottom to top with the 2026 YZ125 jetting spec. I have no complaints!
Hard to say if this is the best jetting spec I have tested, but I can say it feels equal to the best setting I have tested.
I did not make any adjustments all day, just ran it as it’s listed in the manual. Air temperature was 80 to 90 degrees.
If you are considering a 2026 YZ125 I would be excited that they have the jetting sorted and you shouldn’t have to go down this long path of getting the bike to run as it should.
172 main
65 Pilot
N3EW-2 needle
90 power jet (95 was not available)
2.5 out on AS
#7 slide
5.5mm Float Height
80 to 90 degree air temp
Avgas mixed 50/50 with 93 pump
Motul 800 mixed at 32-1
Intermediate level MX rider
My bike is a 2024 YZ125X with Apex SX head and full FMF exhaust.
If the jetting is really good the CDI and intake boot could add up
Interesting, very different intake and the settings work. So maybe the '26 settings are not bueno on the '26. Only bc stawk settings are usually is off. Just sayin'
Im on the PC recommended settings, I can still provoke a lean bog with a jab at the throttle.
Now I have a 5.5 slide I would try, but would suspect that I need a way leaner pilot. What would be a good starting point?
Pit Row
Interesting! Thanks for sharing. I actually landed on the best jetting yet on my '23 125X using 168M, 68P, 70PJ, Y4 needle clip 4, AS 1.5 out at 40:1. Only took me 2 years to figure out! The last change I made since it was lacking a little in the upper RPM's was putting in the GYTR power jet (70) and it really helped. Once I felt the change, I was thinking it could go even bigger so that is especially interesting they are going with the 90PJ.
Sounds like they haven't moved away from the lean slide... just are adjusting intake/jetting/CDI around it..
Glad to hear you felt a marked improvement, but wouldn't a power jet change only affect the lower half of the RPM range (sub 7k~8.5k)?
Thanks! I felt it mostly in the mid / mid to upper transition... maybe the added fuel just gets you into the upper RPM's a tad quicker and that's what I felt.
I was able to test this jetting spec for the 2nd time today. Raced a cross country event that had all types of terrain and it was a good all around test for the jetting.
Jetting worked amazing! Absolutely no complaints. This jetting has a lot of torque below the Powerband. Very good for woods racing. Temps were 95 degrees and high humidity. Bike ran phenomenal. I didn’t make any adjustments, it’s crisp and clean throughout the rev range with plenty of power.
If anyone is still struggling to get your jetting dialed in, the 2026 YZ125 OEM jetting spec is very good, for me.
Once the 2026 YZ125 CDI is available I plan to buy one and try it on my bike to see how it performs but it is hard to think it can be improved from how it ran today.
As temperatures come down in the fall it should only run better and better. These bikes are typically tough to get dialed in the high heat and humidity of the summer but Yamaha seems to have it figured out.
Rocket what's your elevation?
I'm trying to set this bike for the woods has anybody considered an NECJ needle? I am riding at 5000 feet weather in the 70s
No elevation, I’m at sea level.
Not the NECJ, but I have used the N3CJ needle in clip position 3 for the summertime weather. It worked really good. That was my last jetting setup before going to the 2026 YZ125 OEM jetting spec.
I was using the 5.65 slide with the N3CJ needle.
Thanks for the info i Will tinker with the jetting.
Have you tried the gytr jet kit with Y4 needle? Just wondering if the 2026 settings are better. I'm running 68p, y4 3rd clip, 170 main, 70 power jet, stock air screw @ 1.5 turns out. Stock bike with pro circuit storty. 32:1 25% avgas with non ethanol pump fuel. Bike runs clean and strong. Thanks!
I tried using the Y4 needle with several different jetting combinations and could never get my 2024 YZ125X to run the way I think it should.
Many people like the Y4 needle, for me it did not run well.
Rocket what jetting were You running with the N3CJ?
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