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

AJ565
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2096
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3/12/2012
Location
San Antonio, TX US
5/29/2022 8:19pm
etters312 wrote:
So I followed the jetting you have here for my 2018 250sx. The one with the 5.5 slide. And the bike won't really run at all...
So I followed the jetting you have here for my 2018 250sx. The one with the 5.5 slide. And the bike won't really run at all with the choke off. And with choke on it will half ass run but bogs down and shuts off. I run ethanol free 90 octane gas mixed 50:1 with castor 927. And my elevation I ride in varies from 900'-1400'. Any input would be awesome. I'm lost haha
AJ565 wrote:
You replaced everything listed yes? Did you replace the jet block gasket yet? Reeds good? Float height right? If you’ve done those things personally I would...
You replaced everything listed yes? Did you replace the jet block gasket yet? Reeds good? Float height right?

If you’ve done those things personally I would change to a different oil and run it 55:1 or 60:1 and see what happens. I’ve read about some having issues with 927.
etters312 wrote:
I replaced everything listed with your recommendations. Did not replace jet block gasket. Reeds are good, no chips or cracks. They look perfect. I dont know...
I replaced everything listed with your recommendations. Did not replace jet block gasket. Reeds are good, no chips or cracks. They look perfect. I dont know how to set float height. Would the needle clip need to be down more than the 2 slot because of elevation? Idk what effect the changing of slots has. Coming from efi 4 strokes so I'm a noob to all of this. Trying to understand how it all works.
Replace the gasket and see how it runs. That gasket is a known fail point and will make it run funny. That’s where I’d start if it was my bike. The elevation shouldn’t be enough to mess with anything. I’m at 650’ so not too far off and there are guys running this jetting much higher and it’s been stable.
Mx451
Posts
193
Joined
6/15/2018
Location
Bozeman, MT US
5/30/2022 9:47am
AJ565 wrote:
Replace the gasket and see how it runs. That gasket is a known fail point and will make it run funny. That’s where I’d start if...
Replace the gasket and see how it runs. That gasket is a known fail point and will make it run funny. That’s where I’d start if it was my bike. The elevation shouldn’t be enough to mess with anything. I’m at 650’ so not too far off and there are guys running this jetting much higher and it’s been stable.
I'm at 4500' and running first page specs on a 2019 125sx. Runs perfect! Only other mods are PC pipe and silencer. Frankly i was shocked how well it worked this much higher. Thanks AJ!
FGR01
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AZ US
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5/30/2022 2:15pm
AJ565 wrote:
Replace the gasket and see how it runs. That gasket is a known fail point and will make it run funny. That’s where I’d start if...
Replace the gasket and see how it runs. That gasket is a known fail point and will make it run funny. That’s where I’d start if it was my bike. The elevation shouldn’t be enough to mess with anything. I’m at 650’ so not too far off and there are guys running this jetting much higher and it’s been stable.
Mx451 wrote:
I'm at 4500' and running first page specs on a 2019 125sx. Runs perfect! Only other mods are PC pipe and silencer. Frankly i was shocked...
I'm at 4500' and running first page specs on a 2019 125sx. Runs perfect! Only other mods are PC pipe and silencer. Frankly i was shocked how well it worked this much higher. Thanks AJ!
Yup, same here. On my TC125 I go from 600' to 5,000' with the jetting and don't really need to change for those elevations. I am actually slightly richer than the page-1 specs to account for running AvGas.
etters312
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8
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5/27/2022
Location
Karthaus, PA US
6/3/2022 3:14pm
AJ565 wrote:
You replaced everything listed yes? Did you replace the jet block gasket yet? Reeds good? Float height right? If you’ve done those things personally I would...
You replaced everything listed yes? Did you replace the jet block gasket yet? Reeds good? Float height right?

If you’ve done those things personally I would change to a different oil and run it 55:1 or 60:1 and see what happens. I’ve read about some having issues with 927.
etters312 wrote:
I replaced everything listed with your recommendations. Did not replace jet block gasket. Reeds are good, no chips or cracks. They look perfect. I dont know...
I replaced everything listed with your recommendations. Did not replace jet block gasket. Reeds are good, no chips or cracks. They look perfect. I dont know how to set float height. Would the needle clip need to be down more than the 2 slot because of elevation? Idk what effect the changing of slots has. Coming from efi 4 strokes so I'm a noob to all of this. Trying to understand how it all works.
AJ565 wrote:
Replace the gasket and see how it runs. That gasket is a known fail point and will make it run funny. That’s where I’d start if...
Replace the gasket and see how it runs. That gasket is a known fail point and will make it run funny. That’s where I’d start if it was my bike. The elevation shouldn’t be enough to mess with anything. I’m at 650’ so not too far off and there are guys running this jetting much higher and it’s been stable.
So... I took it all back apart. My float height was way off somehow. I got that set. Also my float valve o-ring had gotten pinched and wasn't sealing completely and dumping fuel out the overflow . Replaced that. Put it back together. Fired up first kick. Had to adjust my air screw in to 1/2 a turn out to get it right and not falling on its face off the start but it's running amazing now. Thank you for all of your help and specs!

The Shop

jcp411
Posts
109
Joined
12/26/2018
Location
Denton, TX US
6/4/2022 1:01pm
Well i got the mikuni working with some help.
2022 KTM 125xc
#5 slide
32.5 pj
42-71 needle 3rd clip
490 main
S4 needle jet
90-100 degrees 600ft
Bike runs great no off idle bog
Then the temps dropped to the 70’s and it ran like crap!
Pulled the mikuni off the bike and installed a keihin air striker 38 and with some help getting the jetting dailed in its sooo much better in every way. Very crisp!
1
etters312
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Karthaus, PA US
6/5/2022 8:17am
etters312 wrote:
I replaced everything listed with your recommendations. Did not replace jet block gasket. Reeds are good, no chips or cracks. They look perfect. I dont know...
I replaced everything listed with your recommendations. Did not replace jet block gasket. Reeds are good, no chips or cracks. They look perfect. I dont know how to set float height. Would the needle clip need to be down more than the 2 slot because of elevation? Idk what effect the changing of slots has. Coming from efi 4 strokes so I'm a noob to all of this. Trying to understand how it all works.
AJ565 wrote:
Replace the gasket and see how it runs. That gasket is a known fail point and will make it run funny. That’s where I’d start if...
Replace the gasket and see how it runs. That gasket is a known fail point and will make it run funny. That’s where I’d start if it was my bike. The elevation shouldn’t be enough to mess with anything. I’m at 650’ so not too far off and there are guys running this jetting much higher and it’s been stable.
etters312 wrote:
So... I took it all back apart. My float height was way off somehow. I got that set. Also my float valve o-ring had gotten pinched...
So... I took it all back apart. My float height was way off somehow. I got that set. Also my float valve o-ring had gotten pinched and wasn't sealing completely and dumping fuel out the overflow . Replaced that. Put it back together. Fired up first kick. Had to adjust my air screw in to 1/2 a turn out to get it right and not falling on its face off the start but it's running amazing now. Thank you for all of your help and specs!
I'm getting a TON of smoke. I'm thinking switching back to 60:1 from 50:1
Tuplavee
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Location
FI
6/5/2022 11:09am
My Tc250 is actually running quite fine with
4.0 slide / 43-73 / 3rd clip / PJ 37,5 / MJ 460 / 50:1 / 8mm float level / looped overflow / air screw 2,75 turns out (I know, should be less). Plug color is quite light.

Thinking that if I should even cancel my back ordered 5.5 slide, could it be better?
AJ565
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Location
San Antonio, TX US
6/5/2022 4:38pm
AJ565 wrote:
Replace the gasket and see how it runs. That gasket is a known fail point and will make it run funny. That’s where I’d start if...
Replace the gasket and see how it runs. That gasket is a known fail point and will make it run funny. That’s where I’d start if it was my bike. The elevation shouldn’t be enough to mess with anything. I’m at 650’ so not too far off and there are guys running this jetting much higher and it’s been stable.
etters312 wrote:
So... I took it all back apart. My float height was way off somehow. I got that set. Also my float valve o-ring had gotten pinched...
So... I took it all back apart. My float height was way off somehow. I got that set. Also my float valve o-ring had gotten pinched and wasn't sealing completely and dumping fuel out the overflow . Replaced that. Put it back together. Fired up first kick. Had to adjust my air screw in to 1/2 a turn out to get it right and not falling on its face off the start but it's running amazing now. Thank you for all of your help and specs!
etters312 wrote:
I'm getting a TON of smoke. I'm thinking switching back to 60:1 from 50:1
Drop the needle one clip.
AJ565
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San Antonio, TX US
6/5/2022 4:39pm
Tuplavee wrote:
My Tc250 is actually running quite fine with 4.0 slide / 43-73 / 3rd clip / PJ 37,5 / MJ 460 / 50:1 / 8mm float...
My Tc250 is actually running quite fine with
4.0 slide / 43-73 / 3rd clip / PJ 37,5 / MJ 460 / 50:1 / 8mm float level / looped overflow / air screw 2,75 turns out (I know, should be less). Plug color is quite light.

Thinking that if I should even cancel my back ordered 5.5 slide, could it be better?
It’s way better. Hopefully someone else that’s tried to keep stock and switched it up so it’s not just me saying that.
1
6/5/2022 6:32pm
AJ565 wrote:
It’s way better. Hopefully someone else that’s tried to keep stock and switched it up so it’s not just me saying that.
The top end is way better, just keeps pulling longer compared to stock. On the track I think that would make a huge difference in how long you can pull a gear. Before it was all mid range nothing up top. For me I ride woods and the consistency is way better which for me was the biggest thing. Never knew how it would run before. A 5c temp change would throw it off. Now can pretty much ride all season with just turning air screw.
Mx451
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Location
Bozeman, MT US
6/6/2022 4:36am
AJ565 wrote:
It’s way better. Hopefully someone else that’s tried to keep stock and switched it up so it’s not just me saying that.
22 Tc250 owner here. When i switched everything out it was like a whole new bike. Pulled harder everywhere, was much more crisp, and more stable across varying atmospheric conditions. Like going from a stock to a mod bike.
6/6/2022 6:28am
If anyone if interested in trying this jetting setup I have a kit available in the For Sale/Bazaar forum. I sold my 18 250SX and used this jetting setup for about 20 hrs. All the comments are spot on, it really cleans up the bottom end and better transition into a more usable top end power.
etters312
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Location
Karthaus, PA US
6/10/2022 8:34pm
etters312 wrote:
So... I took it all back apart. My float height was way off somehow. I got that set. Also my float valve o-ring had gotten pinched...
So... I took it all back apart. My float height was way off somehow. I got that set. Also my float valve o-ring had gotten pinched and wasn't sealing completely and dumping fuel out the overflow . Replaced that. Put it back together. Fired up first kick. Had to adjust my air screw in to 1/2 a turn out to get it right and not falling on its face off the start but it's running amazing now. Thank you for all of your help and specs!
etters312 wrote:
I'm getting a TON of smoke. I'm thinking switching back to 60:1 from 50:1
AJ565 wrote:
Drop the needle one clip.
I dropped the needle down to the 1 position for the clip. Still lots of smoke. Bog off idle like to start moving. If I turn the air screw in the whole way it doesn't bog but still lots of smoke. I'm going to switch from Castor 927 to Amsoil dominator. Would you think I'd need to change my mix ratio or my pilot jet size also? Needle with clip in the 1 position and air screw all the way in would be leaning out my pilot correct?
FGR01
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6/10/2022 8:50pm
etters312 wrote:
I'm getting a TON of smoke. I'm thinking switching back to 60:1 from 50:1
AJ565 wrote:
Drop the needle one clip.
etters312 wrote:
I dropped the needle down to the 1 position for the clip. Still lots of smoke. Bog off idle like to start moving. If I turn...
I dropped the needle down to the 1 position for the clip. Still lots of smoke. Bog off idle like to start moving. If I turn the air screw in the whole way it doesn't bog but still lots of smoke. I'm going to switch from Castor 927 to Amsoil dominator. Would you think I'd need to change my mix ratio or my pilot jet size also? Needle with clip in the 1 position and air screw all the way in would be leaning out my pilot correct?
Air screw all the way in is completely closing off the air passage way. Max rich. Try going the other way. Start at 1.5 open and work more open in 1/4 turn increments blipping the throttle until you get best/clean response. If you need to go more than 2.25 turns open it's time to start thinking about a leaner pilot.

yeah, I agree with getting rid of the 927 and copying AJ's oil and ratio.
etters312
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Karthaus, PA US
6/11/2022 2:33pm
AJ565 wrote:
Drop the needle one clip.
etters312 wrote:
I dropped the needle down to the 1 position for the clip. Still lots of smoke. Bog off idle like to start moving. If I turn...
I dropped the needle down to the 1 position for the clip. Still lots of smoke. Bog off idle like to start moving. If I turn the air screw in the whole way it doesn't bog but still lots of smoke. I'm going to switch from Castor 927 to Amsoil dominator. Would you think I'd need to change my mix ratio or my pilot jet size also? Needle with clip in the 1 position and air screw all the way in would be leaning out my pilot correct?
FGR01 wrote:
Air screw all the way in is completely closing off the air passage way. Max rich. Try going the other way. Start at 1.5 open and...
Air screw all the way in is completely closing off the air passage way. Max rich. Try going the other way. Start at 1.5 open and work more open in 1/4 turn increments blipping the throttle until you get best/clean response. If you need to go more than 2.25 turns open it's time to start thinking about a leaner pilot.

yeah, I agree with getting rid of the 927 and copying AJ's oil and ratio.
Turning screw out made it worse so I guess I'm too lean. I moved needle clip to 3 spot. (3rd down from the top) and It works decent with the screw at 1.0 turns out. Might try to move clip to the 4 position and see if it runs and cleaner. It's still not very crisp right at the bottom.
AJ565
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2096
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Location
San Antonio, TX US
6/11/2022 4:04pm
etters312 wrote:
I dropped the needle down to the 1 position for the clip. Still lots of smoke. Bog off idle like to start moving. If I turn...
I dropped the needle down to the 1 position for the clip. Still lots of smoke. Bog off idle like to start moving. If I turn the air screw in the whole way it doesn't bog but still lots of smoke. I'm going to switch from Castor 927 to Amsoil dominator. Would you think I'd need to change my mix ratio or my pilot jet size also? Needle with clip in the 1 position and air screw all the way in would be leaning out my pilot correct?
FGR01 wrote:
Air screw all the way in is completely closing off the air passage way. Max rich. Try going the other way. Start at 1.5 open and...
Air screw all the way in is completely closing off the air passage way. Max rich. Try going the other way. Start at 1.5 open and work more open in 1/4 turn increments blipping the throttle until you get best/clean response. If you need to go more than 2.25 turns open it's time to start thinking about a leaner pilot.

yeah, I agree with getting rid of the 927 and copying AJ's oil and ratio.
etters312 wrote:
Turning screw out made it worse so I guess I'm too lean. I moved needle clip to 3 spot. (3rd down from the top) and It...
Turning screw out made it worse so I guess I'm too lean. I moved needle clip to 3 spot. (3rd down from the top) and It works decent with the screw at 1.0 turns out. Might try to move clip to the 4 position and see if it runs and cleaner. It's still not very crisp right at the bottom.
What exactly is the jetting you have in the bike now and what did you replace? Just so we’re on the same page here.
etters312
Posts
8
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5/27/2022
Location
Karthaus, PA US
6/11/2022 4:33pm
FGR01 wrote:
Air screw all the way in is completely closing off the air passage way. Max rich. Try going the other way. Start at 1.5 open and...
Air screw all the way in is completely closing off the air passage way. Max rich. Try going the other way. Start at 1.5 open and work more open in 1/4 turn increments blipping the throttle until you get best/clean response. If you need to go more than 2.25 turns open it's time to start thinking about a leaner pilot.

yeah, I agree with getting rid of the 927 and copying AJ's oil and ratio.
etters312 wrote:
Turning screw out made it worse so I guess I'm too lean. I moved needle clip to 3 spot. (3rd down from the top) and It...
Turning screw out made it worse so I guess I'm too lean. I moved needle clip to 3 spot. (3rd down from the top) and It works decent with the screw at 1.0 turns out. Might try to move clip to the 4 position and see if it runs and cleaner. It's still not very crisp right at the bottom.
AJ565 wrote:
What exactly is the jetting you have in the bike now and what did you replace? Just so we’re on the same page here.
Solid jetting if you're someone that doesn't live on top end. Crisp down low out of turns pull.
MJ 490
PJ 32.5
AS 1.5 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

This is what is currently all in the bike now. Except Needle clip is on 3rd position at the moment. And it still falls on its face with air screw 1.5 turns out. I replaced the jet block gasket with the JD kit also. At 1 turn out it doesn't fall on its face but it's still sluggish. Runs best with air screw all the way in or almost all the way in.
etters312
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8
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5/27/2022
Location
Karthaus, PA US
6/12/2022 11:56am
etters312 wrote:
Turning screw out made it worse so I guess I'm too lean. I moved needle clip to 3 spot. (3rd down from the top) and It...
Turning screw out made it worse so I guess I'm too lean. I moved needle clip to 3 spot. (3rd down from the top) and It works decent with the screw at 1.0 turns out. Might try to move clip to the 4 position and see if it runs and cleaner. It's still not very crisp right at the bottom.
AJ565 wrote:
What exactly is the jetting you have in the bike now and what did you replace? Just so we’re on the same page here.
etters312 wrote:
Solid jetting if you're someone that doesn't live on top end. Crisp down low out of turns pull. MJ 490 PJ 32.5 AS 1.5 turns out...
Solid jetting if you're someone that doesn't live on top end. Crisp down low out of turns pull.
MJ 490
PJ 32.5
AS 1.5 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

This is what is currently all in the bike now. Except Needle clip is on 3rd position at the moment. And it still falls on its face with air screw 1.5 turns out. I replaced the jet block gasket with the JD kit also. At 1 turn out it doesn't fall on its face but it's still sluggish. Runs best with air screw all the way in or almost all the way in.
Update.... jetting is perfect. Shitty gas was my problem. I live in the middle of nowhere and my town just recently got a gas station. I believe I was the first person to use the ethanol free 90 pump. I questioned the guy about how dark the gas was but he insisted it was normal. Just mixed a jug of amsoil interceptor 60:1 and the gas was a much lighter color this time. Bike runs perfect. Pretty much no smoke at all anymore after it burnt everything that was in the carb. Not sure if the gas was dirty from the new system or if they had some kind of treatment that was in the lines or what.
1
AJ565
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2096
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San Antonio, TX US
6/12/2022 1:07pm
etters312 wrote:
Update.... jetting is perfect. Shitty gas was my problem. I live in the middle of nowhere and my town just recently got a gas station. I...
Update.... jetting is perfect. Shitty gas was my problem. I live in the middle of nowhere and my town just recently got a gas station. I believe I was the first person to use the ethanol free 90 pump. I questioned the guy about how dark the gas was but he insisted it was normal. Just mixed a jug of amsoil interceptor 60:1 and the gas was a much lighter color this time. Bike runs perfect. Pretty much no smoke at all anymore after it burnt everything that was in the carb. Not sure if the gas was dirty from the new system or if they had some kind of treatment that was in the lines or what.
That’ll do it. After reading your other post I was like something else has to be wrong. Chances are that they had something else in that tank that shouldn’t have been in there. Maybe some diesel by mistake or some kind of oil they tested the pumps with. I’ve had bad pump gas get me twice, but I never had any smoke with it.
Bart149
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28
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10/26/2021
Location
Centuria, WI US
6/20/2022 7:41am

KTM 125SX Jetting. We have two 125s with the jetting listed on the first page and it works very good. I am just trying to fine tune it a bit more for the Temp. Trying to read the spark plug. It looks rich at idle and lean on the top end? This is my sons race bike and he lives on the top end most of the time. How do I know if it is lean on the top end?
FGR01
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AZ US
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6/20/2022 8:20am
Bart149 wrote:
[img]https://p.vitalmx.com/photos/forums/2022/06/20/555967/s1200_20220620Plug1.jpg[/img] [b]KTM 125SX Jetting[/b]. We have two 125s with the jetting listed on the first page and it works very good. I am just trying to...

KTM 125SX Jetting. We have two 125s with the jetting listed on the first page and it works very good. I am just trying to fine tune it a bit more for the Temp. Trying to read the spark plug. It looks rich at idle and lean on the top end? This is my sons race bike and he lives on the top end most of the time. How do I know if it is lean on the top end?
What fuel, oil, and ratio are you using? These can affect the jetting.

You can check the main jet by either doing a WOT plug chop test or simply just keep going richer on the main until it gets too thick on top and you start losing the ability to rev out cleanly, then back it off 1 or 2 sizes to the sweet spot.

Bart149
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Location
Centuria, WI US
6/20/2022 8:53am
Mix of pump and race gas. 40:1 Maxima K2
atrdrvr7
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426
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1/15/2013
Location
Houston, TX US
6/23/2022 7:18am
Just installed AJ's specs off page 1 in my 2021 TC250. Mostly ride in Conroe,TX. Elevation 205', temps have been in high 90's pushing into 100 range. I ride all MX.

Bike runs flawlessly! Jetting has never been better. I almost pulled the trigger on a Lectron so glad I didn't. Currently running VP110 mixed with pump 93, 50:1. Thanks for the hook up!
2
AJ565
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San Antonio, TX US
6/23/2022 1:30pm
atrdrvr7 wrote:
Just installed AJ's specs off page 1 in my 2021 TC250. Mostly ride in Conroe,TX. Elevation 205', temps have been in high 90's pushing into 100...
Just installed AJ's specs off page 1 in my 2021 TC250. Mostly ride in Conroe,TX. Elevation 205', temps have been in high 90's pushing into 100 range. I ride all MX.

Bike runs flawlessly! Jetting has never been better. I almost pulled the trigger on a Lectron so glad I didn't. Currently running VP110 mixed with pump 93, 50:1. Thanks for the hook up!
I have many hours at 3P with this jetting and it’s always been great there.
1
Tuplavee
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Location
FI
7/8/2022 11:07am Edited Date/Time 7/8/2022 12:12pm
AJ565 wrote:
You’ll never get it right, the slide is the problem. Countless people have tried and they are just trying to put a bandaid on the problem...
You’ll never get it right, the slide is the problem. Countless people have tried and they are just trying to put a bandaid on the problem inside of fixing it. You can go back through the thread and see that and then they swap the parts and agree that it’s worth it. If cost is a factor for you then way back in this thread somewhere there is measurements to modify the slide yourself or you can even send it out and have it modified pretty cheap.
Tuplavee wrote:
No need to perfect, just optimal with stock parts:) Ok, I'll at least keep looking for slides, maybe my wallet will look another way sometime... So...
No need to perfect, just optimal with stock partsSmile

Ok, I'll at least keep looking for slides, maybe my wallet will look another way sometime...
So 5.75 would be only route for all temperatures even at 0C/32F? Not 5.0 or 5.5?
AJ565 wrote:
You can go with the 5.5 slide setup if you’d like as well. I’ve run the 5.75 slide in the upper 30’s and needed to move...
You can go with the 5.5 slide setup if you’d like as well. I’ve run the 5.75 slide in the upper 30’s and needed to move the clip on the needle one position and put one side bigger pilot in it.
Ok AJ, you were right.
It's better, feels very different.
I'd say crisp, smooth and not so "exciting" on 0 - 3/4 throttle, goes longer on high revs.
Plug color after three sand track sets was about perfect for my understanding.

Did my PB gps laptime on my local track so cant be bad...

Current setup:
RON95E10
50:1 Castrol
PV yellow 1,5 turns in
AS 1,5 turns out
Slide 5.5
MJ 490
PJ 32,5
Needle 6BFY43-75 , 2nd clip (42-75 in order but might not change)
S4 needle jet
Tested at 100m / 23 Celsius

Thanks for crawfishoo for overseas shipping of the slide&jets
1
7/8/2022 5:47pm
Tuplavee wrote:
Ok AJ, you were right. It's better, feels very different. I'd say crisp, smooth and not so "exciting" on 0 - 3/4 throttle, goes longer on...
Ok AJ, you were right.
It's better, feels very different.
I'd say crisp, smooth and not so "exciting" on 0 - 3/4 throttle, goes longer on high revs.
Plug color after three sand track sets was about perfect for my understanding.

Did my PB gps laptime on my local track so cant be bad...

Current setup:
RON95E10
50:1 Castrol
PV yellow 1,5 turns in
AS 1,5 turns out
Slide 5.5
MJ 490
PJ 32,5
Needle 6BFY43-75 , 2nd clip (42-75 in order but might not change)
S4 needle jet
Tested at 100m / 23 Celsius

Thanks for crawfishoo for overseas shipping of the slide&jets
Glad it made it to you okay!
AJ565
Posts
2096
Joined
3/12/2012
Location
San Antonio, TX US
7/8/2022 6:25pm
Tuplavee wrote:
No need to perfect, just optimal with stock parts:) Ok, I'll at least keep looking for slides, maybe my wallet will look another way sometime... So...
No need to perfect, just optimal with stock partsSmile

Ok, I'll at least keep looking for slides, maybe my wallet will look another way sometime...
So 5.75 would be only route for all temperatures even at 0C/32F? Not 5.0 or 5.5?
AJ565 wrote:
You can go with the 5.5 slide setup if you’d like as well. I’ve run the 5.75 slide in the upper 30’s and needed to move...
You can go with the 5.5 slide setup if you’d like as well. I’ve run the 5.75 slide in the upper 30’s and needed to move the clip on the needle one position and put one side bigger pilot in it.
Tuplavee wrote:
Ok AJ, you were right. It's better, feels very different. I'd say crisp, smooth and not so "exciting" on 0 - 3/4 throttle, goes longer on...
Ok AJ, you were right.
It's better, feels very different.
I'd say crisp, smooth and not so "exciting" on 0 - 3/4 throttle, goes longer on high revs.
Plug color after three sand track sets was about perfect for my understanding.

Did my PB gps laptime on my local track so cant be bad...

Current setup:
RON95E10
50:1 Castrol
PV yellow 1,5 turns in
AS 1,5 turns out
Slide 5.5
MJ 490
PJ 32,5
Needle 6BFY43-75 , 2nd clip (42-75 in order but might not change)
S4 needle jet
Tested at 100m / 23 Celsius

Thanks for crawfishoo for overseas shipping of the slide&jets
Have you tried to put a 500 main in it yet? Between the 490 and 500 I was able to pick up a few mph with the extra top end over rev.
Tuplavee
Posts
56
Joined
2/21/2021
Location
FI
7/12/2022 5:21am
AJ565 wrote:
Have you tried to put a 500 main in it yet? Between the 490 and 500 I was able to pick up a few mph with...
Have you tried to put a 500 main in it yet? Between the 490 and 500 I was able to pick up a few mph with the extra top end over rev.
Put 500 in for today., even better. Also changed to red PV spring...👍
2SmokeCJ
Posts
4
Joined
7/11/2022
Location
Browns Valley, CA US
7/12/2022 9:14am
Hey AJ or anyone else who knows. Will the 125 jetting on the first page work on my 22’ TC 125 with a full fmf kit?
FGR01
Posts
5194
Joined
10/1/2006
Location
AZ US
Fantasy
947th
7/12/2022 10:49am Edited Date/Time 7/12/2022 10:52am
2SmokeCJ wrote:
Hey AJ or anyone else who knows. Will the 125 jetting on the first page work on my 22’ TC 125 with a full fmf kit?
I'll try to summarize the 28 pages in a manner that should help with your 22-TC125.

Answer is yes, the jetting is a very good starting point for your bike. I have a 2021-TC125 and am running a close variation of page 1 (my exact specs on later posts throughout)

"Do I really need to buy the slide, etc ?" - YES, you need all the parts to do it right. The slide is the most important part. You are wasting your time dancing around the real issue if you try to shortcut without the slide.

Also, there is a known prob with the 2022 model 125/150. Some bikes just don't seem to jet correctly. Some users on here have tried swapping to known good carbs which seems to fix the prob. So, there is a hypothesis that there is something inherently wrong with some 2022 stock Mikuni carbs that will not allow them to run correctly no matter what jetting.

FMF system - yes, no problem. I am running full-FMF on my bike. I have also used stock, and Bill's. There is very little jetting difference between any of them. It's really just small fine tuning which you'll be doing anyway based on what fuel, oil, and ratio you use and environmental conditions.
2

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