22 YZ125 fouling plugs

WhyZee12345
Edited Date/Time 8/12/2022 5:44pm
Me and my brother both got new 22 yz125 and ride on the trails/enduro but the plugs keep on fouling every half hour. Then read it was maybe the jetting so got a jd jetting kit which was recommended by lots of people who have the new 22s. That did not fix the issue but made it better. More throttle responce, more get up and go but the plugs were fouling still every hour on both bikes. Can someone please help me figure out what I’m doing wrong? And how to fix it!!

Specs (on 2 of the same 2022 yz125 bikes)
32:1 Yamalube 2r
Jd kit jetted for 0-3000 altitude
Always premium
Clean air filter
Under 10 hours both bikes

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sandhills
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sandhills 7/18/2022 7:25pm
7/18/2022 7:25pm
Running the stock BR9EVX for replacements? I only ask cause some people use throwaway BR9ES plugs for tuning and they foul way easier.
WhyZee12345 7/18/2022 7:27pm
7/18/2022 7:27pm
sandhills wrote:
Running the stock BR9EVX for replacements? I only ask cause some people use throwaway BR9ES plugs for tuning and they foul way easier.
I run br9eix and br9es plugs and find no difference in time before fouling the plug.
FGR01
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FGR01 7/18/2022 7:42pm
7/18/2022 7:42pm
Give us the complete jetting specs you put in. Most have found the need to go way down on the pilot.. to like a 50 or 52. Much leaner than stock.
WhyZee12345 7/18/2022 7:46pm
7/18/2022 7:46pm
FGR01 wrote:
Give us the complete jetting specs you put in. Most have found the need to go way down on the pilot.. to like a 50 or...
Give us the complete jetting specs you put in. Most have found the need to go way down on the pilot.. to like a 50 or 52. Much leaner than stock.
50 pilot
Red needle
4th clip
170main

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sandhills
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sandhills 7/18/2022 8:33pm
7/18/2022 8:33pm
I find the EIX fouls less than the ES or EG in my 2003.

Shortcut would be to switch to a BR8 plug, and there is a real argument that it's ok and correct to do so for off road riding. But otherwise it's time to start real tuning beyond just the JD recommended specs. Trying different pilot sizes, mains, clip positions.
chump6784
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chump6784 7/19/2022 12:32am
7/19/2022 12:32am
Mxa have jetting specs for the 22 yz125. They said it came way too rich. Search for their review on it and that should point you in the right direction.

Also, and this will provably cause a shit fight, but 32:1 is too rich, especially for trail/enduro riding. I run 40:1 if I'm riding moto on my wife's yz125 and 50:1 when she's riding
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wrc777
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wrc777 7/19/2022 5:15am
7/19/2022 5:15am
MXA specs are for the track. You need to go leaner jetting for trails/enduro. You probably need a larger diameter needle more than anything else but at least trying going down 1-2 sizes on the pilot first. Also make sure the air screw isn't turned all the way in.

40:1 vs 32:1 oil will make no difference to plug fouling. It is the fuel that fouls the plugs. If anything 32:1 is a touch leaner than 40:1. It will make a difference to how much oil comes out of the exhaust though.
FGR01
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FGR01 7/19/2022 8:11am
7/19/2022 8:11am
Yes, start by dropping the needle down (raising the clip) to clip-3.

On the general topic of oil ratio vs. jetting.....

Leaner oil/gas ratio makes for richer gas/air ratio. In other words, changing from 32:1 to 40:1 will be less oil.. but more gas. Which will cool combustion temps and make more spooge and more fouling. When people see spooge or fouling their natural reaction is to "just put in less oil" but it's not that simple and usually has the opposite of the desired effect.
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WhyZee12345 7/19/2022 8:22am
7/19/2022 8:22am
FGR01 wrote:
Yes, start by dropping the needle down (raising the clip) to clip-3. On the general topic of oil ratio vs. jetting..... Leaner oil/gas ratio makes for...
Yes, start by dropping the needle down (raising the clip) to clip-3.

On the general topic of oil ratio vs. jetting.....

Leaner oil/gas ratio makes for richer gas/air ratio. In other words, changing from 32:1 to 40:1 will be less oil.. but more gas. Which will cool combustion temps and make more spooge and more fouling. When people see spooge or fouling their natural reaction is to "just put in less oil" but it's not that simple and usually has the opposite of the desired effect.
Imo 40:1 is a bit scetchy… don’t wanna blow up a brand new bike
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b_kowalsk
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b_kowalsk 7/19/2022 12:28pm
7/19/2022 12:28pm
FGR01 wrote:
Yes, start by dropping the needle down (raising the clip) to clip-3. On the general topic of oil ratio vs. jetting..... Leaner oil/gas ratio makes for...
Yes, start by dropping the needle down (raising the clip) to clip-3.

On the general topic of oil ratio vs. jetting.....

Leaner oil/gas ratio makes for richer gas/air ratio. In other words, changing from 32:1 to 40:1 will be less oil.. but more gas. Which will cool combustion temps and make more spooge and more fouling. When people see spooge or fouling their natural reaction is to "just put in less oil" but it's not that simple and usually has the opposite of the desired effect.
WhyZee12345 wrote:
Imo 40:1 is a bit scetchy… don’t wanna blow up a brand new bike
Nothing sketchy about 40:1 with modern 2 stroke oils. But that's a different topic all together. Pick a ratio and jet accordingly.
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AJ565
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AJ565 7/19/2022 3:32pm
7/19/2022 3:32pm
FGR01 wrote:
Yes, start by dropping the needle down (raising the clip) to clip-3. On the general topic of oil ratio vs. jetting..... Leaner oil/gas ratio makes for...
Yes, start by dropping the needle down (raising the clip) to clip-3.

On the general topic of oil ratio vs. jetting.....

Leaner oil/gas ratio makes for richer gas/air ratio. In other words, changing from 32:1 to 40:1 will be less oil.. but more gas. Which will cool combustion temps and make more spooge and more fouling. When people see spooge or fouling their natural reaction is to "just put in less oil" but it's not that simple and usually has the opposite of the desired effect.
WhyZee12345 wrote:
Imo 40:1 is a bit scetchy… don’t wanna blow up a brand new bike
It’s not going to blow up at 40:1. KTM stock recommends 40:1 in their 125’s.

What kind of oil are you using? Maybe in addition to getting it jetted right you can switch to a lower flash point oil. I’ve had great luck with amsoil dominator myself.


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WhyZee12345 7/19/2022 10:08pm
7/19/2022 10:08pm
FGR01 wrote:
Yes, start by dropping the needle down (raising the clip) to clip-3. On the general topic of oil ratio vs. jetting..... Leaner oil/gas ratio makes for...
Yes, start by dropping the needle down (raising the clip) to clip-3.

On the general topic of oil ratio vs. jetting.....

Leaner oil/gas ratio makes for richer gas/air ratio. In other words, changing from 32:1 to 40:1 will be less oil.. but more gas. Which will cool combustion temps and make more spooge and more fouling. When people see spooge or fouling their natural reaction is to "just put in less oil" but it's not that simple and usually has the opposite of the desired effect.
WhyZee12345 wrote:
Imo 40:1 is a bit scetchy… don’t wanna blow up a brand new bike
AJ565 wrote:
It’s not going to blow up at 40:1. KTM stock recommends 40:1 in their 125’s. What kind of oil are you using? Maybe in addition to...
It’s not going to blow up at 40:1. KTM stock recommends 40:1 in their 125’s.

What kind of oil are you using? Maybe in addition to getting it jetted right you can switch to a lower flash point oil. I’ve had great luck with amsoil dominator myself.


Yamalube 2r
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Alex814
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Alex814 7/31/2022 1:27pm
7/31/2022 1:27pm
I have the JD jetting kit on my 22 YZ125 as well. It's a 50 pilot and 172 main with the blue needle but still doesn't run too well as OP stated. I ordered some more jets and am going to try going back to stock- big pilot small main, but 1-3 steps leaner on all circuits from standard.
b_kowalsk
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b_kowalsk 7/31/2022 5:01pm
7/31/2022 5:01pm
Alex814 wrote:
I have the JD jetting kit on my 22 YZ125 as well. It's a 50 pilot and 172 main with the blue needle but still doesn't...
I have the JD jetting kit on my 22 YZ125 as well. It's a 50 pilot and 172 main with the blue needle but still doesn't run too well as OP stated. I ordered some more jets and am going to try going back to stock- big pilot small main, but 1-3 steps leaner on all circuits from standard.
I usually end up doing the opposite. Small pilot, big main.
50 pilot still seems large to me however I have no experience with these new 125's. My 250, with that same carb i am running a 45 pilot.
Sounds crazy that those bikes come stock with a 72 pilot?
DynoDan22
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DynoDan22 7/31/2022 8:38pm
7/31/2022 8:38pm
A friend has a ‘22 YZ125 and the stock jetting was atrocious. Here’s where we ended up:

Air Screw: 2 out
Pilot: 58
Needle: NOZK (‘16 KTM 150 optional needle)
Needle Position: 2nd from top
Main: 162
Power Jet: stock
Slide: stock
Float level: stock

Fuel: 50:50 pump/C12 with 40:1 Motorex 2t
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Alex814
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Alex814 7/31/2022 8:50pm
7/31/2022 8:50pm
Alex814 wrote:
I have the JD jetting kit on my 22 YZ125 as well. It's a 50 pilot and 172 main with the blue needle but still doesn't...
I have the JD jetting kit on my 22 YZ125 as well. It's a 50 pilot and 172 main with the blue needle but still doesn't run too well as OP stated. I ordered some more jets and am going to try going back to stock- big pilot small main, but 1-3 steps leaner on all circuits from standard.
b_kowalsk wrote:
I usually end up doing the opposite. Small pilot, big main. 50 pilot still seems large to me however I have no experience with these new...
I usually end up doing the opposite. Small pilot, big main.
50 pilot still seems large to me however I have no experience with these new 125's. My 250, with that same carb i am running a 45 pilot.
Sounds crazy that those bikes come stock with a 72 pilot?
I have a cr250 with this carb as well and running a 45 pilot. Problem is, I don't know if the YZ125 wants to be tuned like a 250 - it has a midrange bog with both of the JD settings so I'm going to try a 70 pilot (75 was stock) and 155 main.
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digger
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digger 8/1/2022 5:38am
8/1/2022 5:38am
IMO, Yamaha has done what KTM did to all of it's post 16' carb'd bikes, which is a cost cutting measure to share the same carb on all of it's carb equipped,125/250 mx bikes. The problem is they are trying to jet around that expensive, to replace slide, with cheap brass, and to me, it doesn't look like they put in much time testing. If it were my bike, I would be putting the smallest power jet, I could get, 35, and starting from there. I would be using a needle series, CCL/CCM, that I know works with the #7 slide in small bore bikes. I know that Yamaha usually use a slightly larger/richer pilot than the KTM's, so I would start at around a 52 pilot, while the main jet is typically smaller than the KTM's, so start at around 170. Set the air screw at 1.5 and test from there. I don't doubt, that if Yamaha had spec'd a #6 slide, they could have used the same N3c/e-x series needles that they use in the 250. I've used that series needle a bunch of times in small bore bikes, but they don't like that #7 slide.
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profeshenal125 8/1/2022 6:15am
8/1/2022 6:15am
They sound rich on the bottom, real blurbiby, slow to get on the pipe. They sound Great tho when they hit the mid range. I easily beat 2 22,s off corners into a steep hill.off the floater I gave them a look back. On a stock pipe 04 cr125.
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Alex814
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Alex814 8/1/2022 10:32am
8/1/2022 10:32am
digger wrote:
IMO, Yamaha has done what KTM did to all of it's post 16' carb'd bikes, which is a cost cutting measure to share the same carb...
IMO, Yamaha has done what KTM did to all of it's post 16' carb'd bikes, which is a cost cutting measure to share the same carb on all of it's carb equipped,125/250 mx bikes. The problem is they are trying to jet around that expensive, to replace slide, with cheap brass, and to me, it doesn't look like they put in much time testing. If it were my bike, I would be putting the smallest power jet, I could get, 35, and starting from there. I would be using a needle series, CCL/CCM, that I know works with the #7 slide in small bore bikes. I know that Yamaha usually use a slightly larger/richer pilot than the KTM's, so I would start at around a 52 pilot, while the main jet is typically smaller than the KTM's, so start at around 170. Set the air screw at 1.5 and test from there. I don't doubt, that if Yamaha had spec'd a #6 slide, they could have used the same N3c/e-x series needles that they use in the 250. I've used that series needle a bunch of times in small bore bikes, but they don't like that #7 slide.
Great info, thanks. I already have an NYEF and a 70 pilot on order, so if going that route doesn't fix the jetting I will get the CCL and CCM.
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Falcon
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Falcon 8/1/2022 10:45am
8/1/2022 10:45am
sandhills wrote:
.....aaaaaand it's an oil thread
Clearly, there's only one oil that should ever be run by anyone, and that is brand _. All other oils will give you the spooge, but brand _ runs perfectly clean, aligns the planets, and will get you laid.
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digger
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digger 8/1/2022 11:09am
8/1/2022 11:09am
DynoDan22 wrote:
A friend has a ‘22 YZ125 and the stock jetting was atrocious. Here’s where we ended up: Air Screw: 2 out Pilot: 58 Needle: NOZK (‘16...
A friend has a ‘22 YZ125 and the stock jetting was atrocious. Here’s where we ended up:

Air Screw: 2 out
Pilot: 58
Needle: NOZK (‘16 KTM 150 optional needle)
Needle Position: 2nd from top
Main: 162
Power Jet: stock
Slide: stock
Float level: stock

Fuel: 50:50 pump/C12 with 40:1 Motorex 2t
IMO, That is a odd setup.
You're using, what I would consider, a really lean K starting diameter needle. I would almost suspect that you are off the straight section of that series needle and into the first taper, at idle. Combined with a rich pilot jet and a really lean, sea level elevation, main. You most be using a big/rich power jet to cover that. I guess if it works and you're happy with it, great.
btroxler
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btroxler 8/1/2022 12:55pm
8/1/2022 12:55pm
Try this:

70 Pilot
155 Main
3rd Clip NYDF Needle
DynoDan22
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DynoDan22 8/1/2022 1:53pm
8/1/2022 1:53pm
The problem with the new 125 is the straight section being too rich. I’ve haven’t seen anyone address this on this thread.
Alex814
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Alex814 8/4/2022 10:36am
8/4/2022 10:36am
btroxler wrote:
Try this:

70 Pilot
155 Main
3rd Clip NYDF Needle
This is what I'm installing but with the next leaner NYEF needle. Will update once I've had a chance to ride it.
moto551
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moto551 8/5/2022 3:56pm
8/5/2022 3:56pm
WhyZee12345 wrote:
Imo 40:1 is a bit scetchy… don’t wanna blow up a brand new bike
AJ565 wrote:
It’s not going to blow up at 40:1. KTM stock recommends 40:1 in their 125’s. What kind of oil are you using? Maybe in addition to...
It’s not going to blow up at 40:1. KTM stock recommends 40:1 in their 125’s.

What kind of oil are you using? Maybe in addition to getting it jetted right you can switch to a lower flash point oil. I’ve had great luck with amsoil dominator myself.


WhyZee12345 wrote:
Yamalube 2r
Stop running yamalube 2r. I always had problems with it unless I mixed it with high octane race gas.

I recommend honda hp2 oil. Cheap and ran much cleaner.
slowoldman
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slowoldman 8/6/2022 4:53pm
8/6/2022 4:53pm
If you get fed up with the stock carb, consider a Lectron Carb. No jets. I have one on my YZ and it’s awesome. Just offering an option. I hope you get it figured out either way. 👍
Alex814
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Alex814 8/12/2022 5:44pm
8/12/2022 5:44pm
digger wrote:
IMO, Yamaha has done what KTM did to all of it's post 16' carb'd bikes, which is a cost cutting measure to share the same carb...
IMO, Yamaha has done what KTM did to all of it's post 16' carb'd bikes, which is a cost cutting measure to share the same carb on all of it's carb equipped,125/250 mx bikes. The problem is they are trying to jet around that expensive, to replace slide, with cheap brass, and to me, it doesn't look like they put in much time testing. If it were my bike, I would be putting the smallest power jet, I could get, 35, and starting from there. I would be using a needle series, CCL/CCM, that I know works with the #7 slide in small bore bikes. I know that Yamaha usually use a slightly larger/richer pilot than the KTM's, so I would start at around a 52 pilot, while the main jet is typically smaller than the KTM's, so start at around 170. Set the air screw at 1.5 and test from there. I don't doubt, that if Yamaha had spec'd a #6 slide, they could have used the same N3c/e-x series needles that they use in the 250. I've used that series needle a bunch of times in small bore bikes, but they don't like that #7 slide.
I ordered the CCL and CCM to try your setting. What clip position do you recommend starting with?
digger
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digger 8/12/2022 9:39pm
8/12/2022 9:39pm
Alex814 wrote:
I ordered the CCL and CCM to try your setting. What clip position do you recommend starting with?
I always try to startout on clip position #3. I'm thinking you should be in the #2 to #3 range.

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