2006 YZ250 Jetting tits

layenpipe25
Posts
55
Joined
2/12/2019
Location
Simi Valley, CA US
3/7/2019 11:25am Edited Date/Time 3/17/2019 7:38am
I need to jet this 2006 yz250 I picked up.It runs rich and is fouling plugs. I know someone on here has the titty set up. Please share!

Bike specs:
FMF gnarly pipe with turbine core sparky
vforce3 reed valve system
Premix is 50:1 Motul 800 2T
I am in southern California and ride in elevations between 500 - 2500 ft.
It currently has a 52 pilot and the main is unknown(No label found - Does that mean it's stock?). I haven't checked the needle yet.

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digger
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736
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4/1/2008
Location
Upstate, NY US
Fantasy
3803rd
3/7/2019 12:01pm
I need to jet this 2006 yz250 I picked up.It runs rich and is fouling plugs. I know someone on here has the titty set up...
I need to jet this 2006 yz250 I picked up.It runs rich and is fouling plugs. I know someone on here has the titty set up. Please share!

Bike specs:
FMF gnarly pipe with turbine core sparky
vforce3 reed valve system
Premix is 50:1 Motul 800 2T
I am in southern California and ride in elevations between 500 - 2500 ft.
It currently has a 52 pilot and the main is unknown(No label found - Does that mean it's stock?). I haven't checked the needle yet.

Needle--Suzuki NECJ in the #3 clip position https://www.rockymountainatvmc.com/oem-schematic/2

Pilot Jet--42

Main--172/170

Power Jet---40 https://www.rockymountainatvmc.com/parts/keihin-n424-52-series-leak-jet… The 2t power jet is the exact same jet as a 4t leak jet. Same exact jet, two different names.

Air Screw---1.5 turns out
1
stimpy
Posts
8
Joined
9/22/2018
Location
GB
3/7/2019 1:53pm
178 main , 48 or 50 pilot. 2nd clip on needle. Ditch the turbine core if you dont need it.

Should put you in ball park and not risk being on the lean side.
2
AJ565
Posts
2075
Joined
3/12/2012
Location
San Antonio, TX US
3/8/2019 8:49am
I need to jet this 2006 yz250 I picked up.It runs rich and is fouling plugs. I know someone on here has the titty set up...
I need to jet this 2006 yz250 I picked up.It runs rich and is fouling plugs. I know someone on here has the titty set up. Please share!

Bike specs:
FMF gnarly pipe with turbine core sparky
vforce3 reed valve system
Premix is 50:1 Motul 800 2T
I am in southern California and ride in elevations between 500 - 2500 ft.
It currently has a 52 pilot and the main is unknown(No label found - Does that mean it's stock?). I haven't checked the needle yet.

digger wrote:
Needle--Suzuki NECJ in the #3 clip position https://www.rockymountainatvmc.com/oem-schematic/2 Pilot Jet--42 Main--172/170 Power Jet---40 https://www.rockymountainatvmc.com/parts/keihin-n424-52-series-leak-jet-p The 2t power jet is the exact same jet as a 4t...
Needle--Suzuki NECJ in the #3 clip position https://www.rockymountainatvmc.com/oem-schematic/2

Pilot Jet--42

Main--172/170

Power Jet---40 https://www.rockymountainatvmc.com/parts/keihin-n424-52-series-leak-jet… The 2t power jet is the exact same jet as a 4t leak jet. Same exact jet, two different names.

Air Screw---1.5 turns out
Listen to this guy, he knows his stuff.
3

The Shop

layenpipe25
Posts
55
Joined
2/12/2019
Location
Simi Valley, CA US
3/8/2019 9:43am
I need to jet this 2006 yz250 I picked up.It runs rich and is fouling plugs. I know someone on here has the titty set up...
I need to jet this 2006 yz250 I picked up.It runs rich and is fouling plugs. I know someone on here has the titty set up. Please share!

Bike specs:
FMF gnarly pipe with turbine core sparky
vforce3 reed valve system
Premix is 50:1 Motul 800 2T
I am in southern California and ride in elevations between 500 - 2500 ft.
It currently has a 52 pilot and the main is unknown(No label found - Does that mean it's stock?). I haven't checked the needle yet.

digger wrote:
Needle--Suzuki NECJ in the #3 clip position https://www.rockymountainatvmc.com/oem-schematic/2 Pilot Jet--42 Main--172/170 Power Jet---40 https://www.rockymountainatvmc.com/parts/keihin-n424-52-series-leak-jet-p The 2t power jet is the exact same jet as a 4t...
Needle--Suzuki NECJ in the #3 clip position https://www.rockymountainatvmc.com/oem-schematic/2

Pilot Jet--42

Main--172/170

Power Jet---40 https://www.rockymountainatvmc.com/parts/keihin-n424-52-series-leak-jet… The 2t power jet is the exact same jet as a 4t leak jet. Same exact jet, two different names.

Air Screw---1.5 turns out
Wow this is a pretty significant change. Not going to lie, a little scared to throw this combo in right off the bat.. mostly due to the fact that I am riding the desert tomorrow and won't be able to make any changes in the case it doesn't pan out. That suzuki needle is something that will have to be ordered. My local shop only has the jets in stock. Can you recommend a jet only set up, progressesing toward your intial recommendation for my ride tomorrow?
digger
Posts
736
Joined
4/1/2008
Location
Upstate, NY US
Fantasy
3803rd
3/8/2019 6:09pm Edited Date/Time 3/8/2019 6:12pm
Wow this is a pretty significant change. Not going to lie, a little scared to throw this combo in right off the bat.. mostly due to...
Wow this is a pretty significant change. Not going to lie, a little scared to throw this combo in right off the bat.. mostly due to the fact that I am riding the desert tomorrow and won't be able to make any changes in the case it doesn't pan out. That suzuki needle is something that will have to be ordered. My local shop only has the jets in stock. Can you recommend a jet only set up, progressesing toward your intial recommendation for my ride tomorrow?
The jetting changes I listed above are designed around that Suzuki triple taper needle. The duel taper needle(N3CW) that is currently in your bike requires different jetting. If you only want jetting around your current needle, I would start by putting the needle, N3CW, in the #2 clip with a 48 pilot, and a 175 main jet. Ideally the bike needs the power jet changed to a 38 with this setup. Regardless of which needle you use this bike really likes having a leaner slide. Your current slide is a #7, the bike runs much cleaner with a #8

. https://jdjetting.com/product/jdkh13-keihin-pwk-carburetor-slide-size-8/ The #7 can also be cut into a #8 fairly easily and cheaply.
layenpipe25
Posts
55
Joined
2/12/2019
Location
Simi Valley, CA US
3/13/2019 3:28pm Edited Date/Time 3/13/2019 3:42pm
Wow this is a pretty significant change. Not going to lie, a little scared to throw this combo in right off the bat.. mostly due to...
Wow this is a pretty significant change. Not going to lie, a little scared to throw this combo in right off the bat.. mostly due to the fact that I am riding the desert tomorrow and won't be able to make any changes in the case it doesn't pan out. That suzuki needle is something that will have to be ordered. My local shop only has the jets in stock. Can you recommend a jet only set up, progressesing toward your intial recommendation for my ride tomorrow?
digger wrote:
The jetting changes I listed above are designed around that Suzuki triple taper needle. The duel taper needle(N3CW) that is currently in your bike requires different...
The jetting changes I listed above are designed around that Suzuki triple taper needle. The duel taper needle(N3CW) that is currently in your bike requires different jetting. If you only want jetting around your current needle, I would start by putting the needle, N3CW, in the #2 clip with a 48 pilot, and a 175 main jet. Ideally the bike needs the power jet changed to a 38 with this setup. Regardless of which needle you use this bike really likes having a leaner slide. Your current slide is a #7, the bike runs much cleaner with a #8

. https://jdjetting.com/product/jdkh13-keihin-pwk-carburetor-slide-size-8/ The #7 can also be cut into a #8 fairly easily and cheaply.
The stock needle in my bike is N3EJ.

My bike was running rich and my local shop only had a few jets in stock for my weekend ride so I went with a 48 pilot from a 52, 178 main(stock), and needle set to 2nd clip. It definitely improved and ran more crisp but when letting off full throttle it would wined out making a dinggg...dinggg...dingg. Does that mean I am running lean on the needle? The low seems to be fine... But my plug shows I am running lean somewhere as the electrodes appear to be getting really hot. Still getting a good amount of splooge out the exhaust. Would switching to the popular N3EW improve on this?
AJ565
Posts
2075
Joined
3/12/2012
Location
San Antonio, TX US
3/14/2019 6:24am
Order up what digger suggested. I did with my bike and it went from crap everyone complains about to raped ape. The dude knows his jetting better than anyone on this board.
2
mattyhamz2
Posts
10850
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Location
So Cal, CA US
Fantasy
760th
3/14/2019 9:30am
I'm honestly running stock jetting, C12 mixed 40:1 and my 05 runs perfect!
digger
Posts
736
Joined
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Location
Upstate, NY US
Fantasy
3803rd
3/17/2019 7:38am
Wow this is a pretty significant change. Not going to lie, a little scared to throw this combo in right off the bat.. mostly due to...
Wow this is a pretty significant change. Not going to lie, a little scared to throw this combo in right off the bat.. mostly due to the fact that I am riding the desert tomorrow and won't be able to make any changes in the case it doesn't pan out. That suzuki needle is something that will have to be ordered. My local shop only has the jets in stock. Can you recommend a jet only set up, progressesing toward your intial recommendation for my ride tomorrow?
digger wrote:
The jetting changes I listed above are designed around that Suzuki triple taper needle. The duel taper needle(N3CW) that is currently in your bike requires different...
The jetting changes I listed above are designed around that Suzuki triple taper needle. The duel taper needle(N3CW) that is currently in your bike requires different jetting. If you only want jetting around your current needle, I would start by putting the needle, N3CW, in the #2 clip with a 48 pilot, and a 175 main jet. Ideally the bike needs the power jet changed to a 38 with this setup. Regardless of which needle you use this bike really likes having a leaner slide. Your current slide is a #7, the bike runs much cleaner with a #8

. https://jdjetting.com/product/jdkh13-keihin-pwk-carburetor-slide-size-8/ The #7 can also be cut into a #8 fairly easily and cheaply.
The stock needle in my bike is N3EJ. My bike was running rich and my local shop only had a few jets in stock for my...
The stock needle in my bike is N3EJ.

My bike was running rich and my local shop only had a few jets in stock for my weekend ride so I went with a 48 pilot from a 52, 178 main(stock), and needle set to 2nd clip. It definitely improved and ran more crisp but when letting off full throttle it would wined out making a dinggg...dinggg...dingg. Does that mean I am running lean on the needle? The low seems to be fine... But my plug shows I am running lean somewhere as the electrodes appear to be getting really hot. Still getting a good amount of splooge out the exhaust. Would switching to the popular N3EW improve on this?
From what you are describing, it sounds like a run on idle which is caused by a lean condition. If your bike is good mechanical condition a 48 pilot jet will not run lean with that series needle. The easier thing to do would be to richer the clip position from, the current #2 to the #3 or #4. If that doesn’t work go to the next richer diameter needle, which would be an N3CW as far as you’re concerned.
Cobbler
Posts
432
Joined
3/13/2023
Location
cairo, IL US
4/3/2023 7:28am
I need to jet this 2006 yz250 I picked up.It runs rich and is fouling plugs. I know someone on here has the titty set up...
I need to jet this 2006 yz250 I picked up.It runs rich and is fouling plugs. I know someone on here has the titty set up. Please share!

Bike specs:
FMF gnarly pipe with turbine core sparky
vforce3 reed valve system
Premix is 50:1 Motul 800 2T
I am in southern California and ride in elevations between 500 - 2500 ft.
It currently has a 52 pilot and the main is unknown(No label found - Does that mean it's stock?). I haven't checked the needle yet.

digger wrote:
Needle--Suzuki NECJ in the #3 clip position https://www.rockymountainatvmc.com/oem-schematic/2 Pilot Jet--42 Main--172/170 Power Jet---40 https://www.rockymountainatvmc.com/parts/keihin-n424-52-series-leak-jet-p The 2t power jet is the exact same jet as a 4t...
Needle--Suzuki NECJ in the #3 clip position https://www.rockymountainatvmc.com/oem-schematic/2

Pilot Jet--42

Main--172/170

Power Jet---40 https://www.rockymountainatvmc.com/parts/keihin-n424-52-series-leak-jet… The 2t power jet is the exact same jet as a 4t leak jet. Same exact jet, two different names.

Air Screw---1.5 turns out

Is the suzuki needle as good of a choice as it was on an 06 as it is in a 2021? I'm doing some jetting reading and wondering if this is still the best play.

TheTrackKid
Posts
117
Joined
7/11/2019
Location
Granite Falls, WA US
4/6/2023 6:26am
I need to jet this 2006 yz250 I picked up.It runs rich and is fouling plugs. I know someone on here has the titty set up...
I need to jet this 2006 yz250 I picked up.It runs rich and is fouling plugs. I know someone on here has the titty set up. Please share!

Bike specs:
FMF gnarly pipe with turbine core sparky
vforce3 reed valve system
Premix is 50:1 Motul 800 2T
I am in southern California and ride in elevations between 500 - 2500 ft.
It currently has a 52 pilot and the main is unknown(No label found - Does that mean it's stock?). I haven't checked the needle yet.

digger wrote:
Needle--Suzuki NECJ in the #3 clip position https://www.rockymountainatvmc.com/oem-schematic/2 Pilot Jet--42 Main--172/170 Power Jet---40 https://www.rockymountainatvmc.com/parts/keihin-n424-52-series-leak-jet-p The 2t power jet is the exact same jet as a 4t...
Needle--Suzuki NECJ in the #3 clip position https://www.rockymountainatvmc.com/oem-schematic/2

Pilot Jet--42

Main--172/170

Power Jet---40 https://www.rockymountainatvmc.com/parts/keihin-n424-52-series-leak-jet… The 2t power jet is the exact same jet as a 4t leak jet. Same exact jet, two different names.

Air Screw---1.5 turns out
Cobbler wrote:
Is the suzuki needle as good of a choice as it was on an 06 as it is in a 2021? I'm doing some jetting reading...

Is the suzuki needle as good of a choice as it was on an 06 as it is in a 2021? I'm doing some jetting reading and wondering if this is still the best play.

Yes sir the carb and engine are the same. Will still benefit from the Suzuki needle.

Cobbler
Posts
432
Joined
3/13/2023
Location
cairo, IL US
4/6/2023 10:59am
digger wrote:
Needle--Suzuki NECJ in the #3 clip position https://www.rockymountainatvmc.com/oem-schematic/2 Pilot Jet--42 Main--172/170 Power Jet---40 https://www.rockymountainatvmc.com/parts/keihin-n424-52-series-leak-jet-p The 2t power jet is the exact same jet as a 4t...
Needle--Suzuki NECJ in the #3 clip position https://www.rockymountainatvmc.com/oem-schematic/2

Pilot Jet--42

Main--172/170

Power Jet---40 https://www.rockymountainatvmc.com/parts/keihin-n424-52-series-leak-jet… The 2t power jet is the exact same jet as a 4t leak jet. Same exact jet, two different names.

Air Screw---1.5 turns out
Cobbler wrote:
Is the suzuki needle as good of a choice as it was on an 06 as it is in a 2021? I'm doing some jetting reading...

Is the suzuki needle as good of a choice as it was on an 06 as it is in a 2021? I'm doing some jetting reading and wondering if this is still the best play.

Yes sir the carb and engine are the same. Will still benefit from the Suzuki needle.

Digger really set me up, all the stuff came in the mail today and I'm going to throw it in later MAYBE if I have time. Shouldnt take but a few minutes so I think I'm going to have to try it lol but i'm wary of being on a brand new setup at the track. Could probably get a plug chop in this evening thoughLaughing

1
4/6/2023 5:05pm Edited Date/Time 4/6/2023 5:08pm

IMO, the N3CJ and NECJ needles are both good needles for the YZ. From 40mm up the needle to 20mm they are basically the same. At 20mm the "E" is about 0.001" smaller. At 10mm the "3" is 0.080" diam. and the "E" is 0.073". Then at 2mm they are 0.072" and 0.056", respectively.

So, from 1/2 throttle on is where the difference is. The "E" will deliver more fuel from 1/2 throttle. From closed to 1/2 they are the same.

I've heard a lot of people say it how much better it is on the bottom, but that's really because of the "J" diameter more so than the "E" series taper. The "3" series "J" will do the same for you from 0 to 1/2. 

But the "E" series delivers more fuel at wide open, so you have to drop about 2 or 3 jet sizes. That also works well with dropping the power jet to a 40, 38 or even a 35, since from half throttle on is where the "E" needle starts delivering more fuel and the power jet starts doing its thing. But you may be a clip richer than the "3" to get you through the half throttle ping. 

If you do the "3" series, then a smaller power jet isn't as big a deal. Some guys think it's fine and some think it helps. I think it's got a lot to do with how you ride. 

2

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