150 sx 2025 - review ?

4/20/2025 5:47pm Edited Date/Time 4/20/2025 5:52pm

I’m still holding on to my 2018 150. Love that bike. Such a fun light bike. Never overheats. Easy to cut inside lines, change direction. I downright abuse the clutch and it handles it no problem. I’m sure the newer one’s once sorted out would be worth it and just as fun if not better. Buy the bike, post a proper “spoke with my wallet post”.  

2
burn1986
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bossier city, LA US
4/20/2025 8:33pm
I’m still holding on to my 2018 150. Love that bike. Such a fun light bike. Never overheats. Easy to cut inside lines, change direction. I...

I’m still holding on to my 2018 150. Love that bike. Such a fun light bike. Never overheats. Easy to cut inside lines, change direction. I downright abuse the clutch and it handles it no problem. I’m sure the newer one’s once sorted out would be worth it and just as fun if not better. Buy the bike, post a proper “spoke with my wallet post”.  

The biggest changes to newer ones (up to 2022) is the plastics and graphics fwiw

AssangeMX
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4/20/2025 9:39pm
I’m still holding on to my 2018 150. Love that bike. Such a fun light bike. Never overheats. Easy to cut inside lines, change direction. I...

I’m still holding on to my 2018 150. Love that bike. Such a fun light bike. Never overheats. Easy to cut inside lines, change direction. I downright abuse the clutch and it handles it no problem. I’m sure the newer one’s once sorted out would be worth it and just as fun if not better. Buy the bike, post a proper “spoke with my wallet post”.  

Me too, no point selling my 2018 150.

Just bought the 150 kit to upgrade our 2018 tc125, such good value.

But biting rhe bullet and getting my 19 year old a 250F. He went to bed as a scrawny 18 year old and woke up the next day as a 19 year old brick shithouse!!!

 

Interested to hear what gearing people on 150s running.

Shame about rhe efi TBI bikes, they didn't need to make them so complicated 

3
4/22/2025 11:53am

Here’s a few engines from 3 Dutch sand riders on the 23,24 Ktm 125.  A good sized pile of engine cases, cranks & failed electric start systems.  Haha 

1
5

The Shop

4/22/2025 12:08pm
AssangeMX wrote:
Me too, no point selling my 2018 150.Just bought the 150 kit to upgrade our 2018 tc125, such good value.But biting rhe bullet and getting my...

Me too, no point selling my 2018 150.

Just bought the 150 kit to upgrade our 2018 tc125, such good value.

But biting rhe bullet and getting my 19 year old a 250F. He went to bed as a scrawny 18 year old and woke up the next day as a 19 year old brick shithouse!!!

 

Interested to hear what gearing people on 150s running.

Shame about rhe efi TBI bikes, they didn't need to make them so complicated 

Never selling my 2016 125 and 150. Best bikes I have ever owned, aside from the stock forks. 

burn1986
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4/22/2025 12:18pm
Here’s a few engines from 3 Dutch sand riders on the 23,24 Ktm 125.  A good sized pile of engine cases, cranks & failed electric start...

Here’s a few engines from 3 Dutch sand riders on the 23,24 Ktm 125.  A good sized pile of engine cases, cranks & failed electric start systems.  Haha 

Was there a photo attached? 😎

3
NSP139
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4/22/2025 12:25pm

Never selling my 22 150sx stock fork is junk lol love the KYB's! Also curious on gearing I'm running 3.615 ratio I've heard going to 3.5 but me and my kid are around 180 pounds and I worry about pulling hills at Glen Helen? 

4/22/2025 1:14pm
Here’s a few engines from 3 Dutch sand riders on the 23,24 Ktm 125.  A good sized pile of engine cases, cranks & failed electric start...

Here’s a few engines from 3 Dutch sand riders on the 23,24 Ktm 125.  A good sized pile of engine cases, cranks & failed electric start systems.  Haha 

burn1986 wrote:

Was there a photo attached? 😎

Pic wouldn’t upload, try again

2
1
Tomok
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4/23/2025 6:50pm Edited Date/Time 10/17/2025 9:36am

20250423 142259.jpg?VersionId=KyRode my 2025 150SX for the first time today. Bike is a rippa! 50/50 C12/93 Motul 800 40:1. FMF Factory Fatty with Pro Circuit Shorty. Adjusted TPS and reset power valve. Just as fast or faster than my 2015 150SX with STIC. Hopefully she stays together.

Update: Added TSP ERM and TSP head. Noticeable power gains!

12
AssangeMX
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4/23/2025 10:05pm
Tomok wrote:
Rode my 2025 150SX for the first time today. Bike is a rippa! 50/50 C12/93 Motul 800 40:1. FMF Factory Fatty with Pro Circuit Shorty. Adjusted...

20250423 142259.jpg?VersionId=KyRode my 2025 150SX for the first time today. Bike is a rippa! 50/50 C12/93 Motul 800 40:1. FMF Factory Fatty with Pro Circuit Shorty. Adjusted TPS and reset power valve. Just as fast or faster than my 2015 150SX with STIC. Hopefully she stays together.

Update: Added TSP ERM and TSP head. Noticeable power gains!

Nice 2025 man!!!

Good choice of mods, 2018 sx150 here with fmf fatty,  pc shorty and stic lol!!!

2
4/24/2025 4:55am
Tomok wrote:
Rode my 2025 150SX for the first time today. Bike is a rippa! 50/50 C12/93 Motul 800 40:1. FMF Factory Fatty with Pro Circuit Shorty. Adjusted...

20250423 142259.jpg?VersionId=KyRode my 2025 150SX for the first time today. Bike is a rippa! 50/50 C12/93 Motul 800 40:1. FMF Factory Fatty with Pro Circuit Shorty. Adjusted TPS and reset power valve. Just as fast or faster than my 2015 150SX with STIC. Hopefully she stays together.

Update: Added TSP ERM and TSP head. Noticeable power gains!

How do you compare the riding of the injection and the carb ? 

NSP139
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4/24/2025 5:26am
Tomok wrote:
Rode my 2025 150SX for the first time today. Bike is a rippa! 50/50 C12/93 Motul 800 40:1. FMF Factory Fatty with Pro Circuit Shorty. Adjusted...

20250423 142259.jpg?VersionId=KyRode my 2025 150SX for the first time today. Bike is a rippa! 50/50 C12/93 Motul 800 40:1. FMF Factory Fatty with Pro Circuit Shorty. Adjusted TPS and reset power valve. Just as fast or faster than my 2015 150SX with STIC. Hopefully she stays together.

Update: Added TSP ERM and TSP head. Noticeable power gains!

AssangeMX wrote:

Nice 2025 man!!!

Good choice of mods, 2018 sx150 here with fmf fatty,  pc shorty and stic lol!!!

I have to ask how does the PC shorty perform better than the FMF shorty? 

Tomok
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4/24/2025 6:09am

How do you compare the riding of the injection and the carb ? 

Basically seems like perfect jetting. No bogs or hesitation. Rips right through the powerband. Color me impressed!

1
1
Tomok
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4/24/2025 6:11am
NSP139 wrote:

I have to ask how does the PC shorty perform better than the FMF shorty? 

I really don't know. This is an old school 2 stroke practice and I've also read that it was the best combo on the dyno. I've done this on my last three 2 stokes and will continue.

1
Johnnydirt
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4/24/2025 7:01am Edited Date/Time 4/24/2025 7:03am
NSP139 wrote:

I have to ask how does the PC shorty perform better than the FMF shorty? 

Tomok wrote:
I really don't know. This is an old school 2 stroke practice and I've also read that it was the best combo on the dyno. I've...

I really don't know. This is an old school 2 stroke practice and I've also read that it was the best combo on the dyno. I've done this on my last three 2 stokes and will continue.

I have had the PC shorty on my 21 and now my 23 125sx with good results.   Both with the stock pipe.  

1
AssangeMX
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4/24/2025 7:09am Edited Date/Time 4/24/2025 7:10am
Tomok wrote:
Rode my 2025 150SX for the first time today. Bike is a rippa! 50/50 C12/93 Motul 800 40:1. FMF Factory Fatty with Pro Circuit Shorty. Adjusted...

20250423 142259.jpg?VersionId=KyRode my 2025 150SX for the first time today. Bike is a rippa! 50/50 C12/93 Motul 800 40:1. FMF Factory Fatty with Pro Circuit Shorty. Adjusted TPS and reset power valve. Just as fast or faster than my 2015 150SX with STIC. Hopefully she stays together.

Update: Added TSP ERM and TSP head. Noticeable power gains!

AssangeMX wrote:

Nice 2025 man!!!

Good choice of mods, 2018 sx150 here with fmf fatty,  pc shorty and stic lol!!!

NSP139 wrote:

I have to ask how does the PC shorty perform better than the FMF shorty? 

On the 2018 150 it does.

The fmf has too small and restricted outlet.

NSP139
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4/24/2025 8:29am
AssangeMX wrote:

Nice 2025 man!!!

Good choice of mods, 2018 sx150 here with fmf fatty,  pc shorty and stic lol!!!

NSP139 wrote:

I have to ask how does the PC shorty perform better than the FMF shorty? 

AssangeMX wrote:

On the 2018 150 it does.

The fmf has too small and restricted outlet.

I have a 22 150 with lots of motor work I may have to try this LOL

urbanlift707
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4/24/2025 8:35am

I feel like this trend started with DV back in the day. I ran the pc shorty fmf combo on all my 2017-2022 Ktm 250/300’s. That was hands down the best combo. I tried it on my 23-25 300’s and the pc pipe is better. For the new tbi 300’s this is what I found. Pc pipe/silencer>fmf pipe/pc silencer>fmf pipe/silencer. 

urbanlift707
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4/24/2025 6:25pm Edited Date/Time 4/24/2025 6:25pm

IMG 7189 0.png?VersionId=SEidDylFbunXEeJust spotted this on Josh’s post…..

1
NSP139
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4/24/2025 6:30pm Edited Date/Time 4/24/2025 6:31pm
Just spotted this on Josh’s post…..

IMG 7189 0.png?VersionId=SEidDylFbunXEeJust spotted this on Josh’s post…..

That's not a stock silencer you can see the pipe sticking out of the end cap my stock FMF shorty does not do that and the hole is a lot smaller🤷‍♂️

NSP139
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4/24/2025 6:32pm Edited Date/Time 4/24/2025 6:43pm
Just spotted this on Josh’s post…..

IMG 7189 0.png?VersionId=SEidDylFbunXEeJust spotted this on Josh’s post…..

Is that a pro circuit silencer with an FMF sticker I'm thinking LOL! I get a little slow at dinner time LOL I see it now🤣

3
4/24/2025 6:48pm
Just spotted this on Josh’s post…..

IMG 7189 0.png?VersionId=SEidDylFbunXEeJust spotted this on Josh’s post…..

NSP139 wrote:

Is that a pro circuit silencer with an FMF sticker I'm thinking LOL! I get a little slow at dinner time LOL I see it now🤣

That’s 110% a Pro Circuit R304 with an FMF sticker. 
 

3
Broseph
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4/24/2025 6:51pm
Just spotted this on Josh’s post…..

IMG 7189 0.png?VersionId=SEidDylFbunXEeJust spotted this on Josh’s post…..

Old gen chassis and carb ftw!

1
AssangeMX
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4/24/2025 6:59pm
Just spotted this on Josh’s post…..

IMG 7189 0.png?VersionId=SEidDylFbunXEeJust spotted this on Josh’s post…..

NSP139 wrote:
That's not a stock silencer you can see the pipe sticking out of the end cap my stock FMF shorty does not do that and the...

That's not a stock silencer you can see the pipe sticking out of the end cap my stock FMF shorty does not do that and the hole is a lot smaller🤷‍♂️

Back in 2018, I bought a bunch of pipes and silencers and other parts and sent them to a friend with same 2018 sx150 and dyno access.

V force did nothing 

Fmf fatty made 1hp.

Most silencers lost power vs stock.  Only one that didn't was pc shorty.

Fwiw, the fmf sx125 shorty is the same can and outlet that came on my 2002 rm125!!!!!!

Interesting that others found the same setup,  ours came from empirical measurements and testing,  not from copying others. 😀

1
4/24/2025 7:35pm
Just spotted this on Josh’s post…..

IMG 7189 0.png?VersionId=SEidDylFbunXEeJust spotted this on Josh’s post…..

NSP139 wrote:
That's not a stock silencer you can see the pipe sticking out of the end cap my stock FMF shorty does not do that and the...

That's not a stock silencer you can see the pipe sticking out of the end cap my stock FMF shorty does not do that and the hole is a lot smaller🤷‍♂️

AssangeMX wrote:
Back in 2018, I bought a bunch of pipes and silencers and other parts and sent them to a friend with same 2018 sx150 and dyno...

Back in 2018, I bought a bunch of pipes and silencers and other parts and sent them to a friend with same 2018 sx150 and dyno access.

V force did nothing 

Fmf fatty made 1hp.

Most silencers lost power vs stock.  Only one that didn't was pc shorty.

Fwiw, the fmf sx125 shorty is the same can and outlet that came on my 2002 rm125!!!!!!

Interesting that others found the same setup,  ours came from empirical measurements and testing,  not from copying others. 😀

How did the HGS do?

AssangeMX
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4/24/2025 7:48pm
NSP139 wrote:
That's not a stock silencer you can see the pipe sticking out of the end cap my stock FMF shorty does not do that and the...

That's not a stock silencer you can see the pipe sticking out of the end cap my stock FMF shorty does not do that and the hole is a lot smaller🤷‍♂️

AssangeMX wrote:
Back in 2018, I bought a bunch of pipes and silencers and other parts and sent them to a friend with same 2018 sx150 and dyno...

Back in 2018, I bought a bunch of pipes and silencers and other parts and sent them to a friend with same 2018 sx150 and dyno access.

V force did nothing 

Fmf fatty made 1hp.

Most silencers lost power vs stock.  Only one that didn't was pc shorty.

Fwiw, the fmf sx125 shorty is the same can and outlet that came on my 2002 rm125!!!!!!

Interesting that others found the same setup,  ours came from empirical measurements and testing,  not from copying others. 😀

Rickyisms wrote:

How did the HGS do?

Not good on the 150...

urbanlift707
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Humboldt, CA US
4/24/2025 7:57pm

I haven’t put my stock pipe and silencer back on to test it again but I swear my bike felt slower when I went from stock to a full pc set up on my 2022 tc125. 

AssangeMX
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4/24/2025 8:18pm
NSP139 wrote:
That's not a stock silencer you can see the pipe sticking out of the end cap my stock FMF shorty does not do that and the...

That's not a stock silencer you can see the pipe sticking out of the end cap my stock FMF shorty does not do that and the hole is a lot smaller🤷‍♂️

AssangeMX wrote:
Back in 2018, I bought a bunch of pipes and silencers and other parts and sent them to a friend with same 2018 sx150 and dyno...

Back in 2018, I bought a bunch of pipes and silencers and other parts and sent them to a friend with same 2018 sx150 and dyno access.

V force did nothing 

Fmf fatty made 1hp.

Most silencers lost power vs stock.  Only one that didn't was pc shorty.

Fwiw, the fmf sx125 shorty is the same can and outlet that came on my 2002 rm125!!!!!!

Interesting that others found the same setup,  ours came from empirical measurements and testing,  not from copying others. 😀

Rickyisms wrote:

How did the HGS do?

If i remember correctly. HGS worked best on 125. On 150, it lost power all the way apart from peak, narrow window.  Not sure we tested the buds hgs carbon silencer, it didn't seem well made and the outlet was very narrow.

Didn't try the PC pipe.

Fwiw, ive done loads of 144s over the years and fatty was always recommended. 

Ive got a box with two 2016thru 2018 ffm fatty, a fmf shorty and a fmf sparky for sale...

2
4/24/2025 8:45pm
Just spotted this on Josh’s post…..

IMG 7189 0.png?VersionId=SEidDylFbunXEeJust spotted this on Josh’s post…..

NSP139 wrote:
That's not a stock silencer you can see the pipe sticking out of the end cap my stock FMF shorty does not do that and the...

That's not a stock silencer you can see the pipe sticking out of the end cap my stock FMF shorty does not do that and the hole is a lot smaller🤷‍♂️

AssangeMX wrote:
Back in 2018, I bought a bunch of pipes and silencers and other parts and sent them to a friend with same 2018 sx150 and dyno...

Back in 2018, I bought a bunch of pipes and silencers and other parts and sent them to a friend with same 2018 sx150 and dyno access.

V force did nothing 

Fmf fatty made 1hp.

Most silencers lost power vs stock.  Only one that didn't was pc shorty.

Fwiw, the fmf sx125 shorty is the same can and outlet that came on my 2002 rm125!!!!!!

Interesting that others found the same setup,  ours came from empirical measurements and testing,  not from copying others. 😀

Cool I tested all kinds of pipes & silencers too.  1 of my bikes came with a fmf fatty & reg silencer. It seemed too big & slowed it down to get going. So I bought a fmf shorty it works great .  I was running a stock pipe Verygood with a pc shorty that worked great .  I sold a bike with the pc shorty.  I hv a pc reg too not quite as quick but works great.  I bought a low hr bike with a pc carbon that will b matched with a hgs pipe.  A 03 kx125 pipe is unbelievably on a 06 on a 04 it’s much different. Much slower to get going & softer hit but then a steady pull threw the mid into a topend that Never stops pulling with 2k + more ovr rev.  Great fast track pipe or slick hard pack .  Fmf is a really good pipe for my bike a much harder hit than a pc but I like both .  I like the super  hard quick hit & the quick rush threw the super wide & strong mid into topend still revs to the moon.  But don’t hv a bare metal pc anymore bike was stolen.  I had a 03 kx125 Doma also I never had a chance to mod it to fit , stolen too.  I like all the pipes the hgs is supposed to b really good a 04 pipe is 02-04 pipe for hgs . A 04 is radically different than the 02-03 . Pc & fmf hv a special 04 pipe so not sure if a hgs would b better.  It’s like summer in Al, Ga . &Tn. Still like winter in Wi. I bought fmf silencer thinking I could work a contingency program with them being that there dumping money into 2-st racing & 125 emx title sponsor.  Nothing big maybe 200 bucks for a top 5 in 125 .  Help me get to the races u know.  A fmf shorty hard to explain but it makes a mod engine sound F ing tough. Like Really hear it’s a mod engine on c12. Where a pc shorty sounds racy on a stock engine. 

1
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wrc777
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Greenwood, IN US
Fantasy
4/25/2025 5:37am
I haven’t put my stock pipe and silencer back on to test it again but I swear my bike felt slower when I went from stock...

I haven’t put my stock pipe and silencer back on to test it again but I swear my bike felt slower when I went from stock to a full pc set up on my 2022 tc125. 

I felt like the PC shorty made that bike hit harder but then run out of steam quick where the stock silencer or FMF 2.1 would be smoother at the hit and pull harder/longer up top. Maybe the shorty just added more power and hit the limiter more quickly though?

1

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