STIC and Keihin 38mm experience on YZ125?

Joko
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Considering replacing the stock Mikuni on my 07YZ144 with a STIC Keihin 38mm airstryker to get more top end. Anyone have any experience with this application? Did it make it make it more peaky with a narrower power spread?
It the STIC claim of 10% increase accurate? Thanks...
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3/29/2020 11:06am
What is a STIC Carb? Never heard of it
3/29/2020 11:44am Edited Date/Time 3/29/2020 11:47am
It's not a carb, it's the piece that the main jet threads into, or the piece the needle slides into, I had one on my yz, could not get lean spot jetted out, did seem to rev quicker but other than that for what I do it wasn't to beneficial in my scenario, as for your yz 125 it might be good or you might notice it, definitely dont think it would lose anything
Bruce372
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3/29/2020 11:54am
Its a lot of investment, figure $300 for the carb and then $350 for the STIC and maybe $75 for the JD needles, and then your time.

If you get the carb from a 2016 SX125, thats the newer Keihin shortbody and no powerjet, so its easier to install on bikes that currently use the Mikuni 38MM like you have on the YZ125 since the screw top PWK is longer and folds up the air filter boot.

I got my 2018SX150 used and it came with the lectron, and like the smartcarb i had on my RM144, ive found the jetless carbs run well, but maybe a bit meh coming off the bottom and a little anemic in the middle....

Compared to that, the bike equipped with the STIC PWK keihin absolutely rips, ive messed around with it a little too much as the inventor has come out with new settings, but now i've got it running really good- the bike growls off the bottom and screams up top, i am 250lbs and it will pull me in 3rd most corners. The bike doesnt feel too short from a 250 smoker to be fair.

On the counter, I stuck one on my kids 2018TC125 that we had running really good on the stock mikuni, and he prefers the mikuni better since he likes the crisp, clean, metered power that the mikuni gives even if it doesnt have the bark of the PWK/STIC... he weighs more than 100lbs less than me LOL and has more talent.

There is a dyno vid on youtube rm125/144 i think.

I do know my friend dynoed the STIC on a ktm150 and it made significant more power over stock through the powerband, especially low through midrange, over rev is nice also.

Ive got the complete spare setup, new carb, STIC, needles, special domino throttle and all that that i took off the kids bike, but not sure i wanna sell it in case i get another 2 stroke.
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Joko
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3/29/2020 5:25pm
Good info, thanks Bruce!
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The Shop

H4L
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3/29/2020 5:37pm Edited Date/Time 3/29/2020 8:13pm
What is a STIC Carb? Never heard of it
Not a carb it's a fuel metering block / tube that goes inside the carb..

http://www.sticsupertorque.com/
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FGR01
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3/29/2020 6:11pm
TL/DR: Putting a PWK with STIC on a newer YZ125 is not a quick bolt and go proposition. If that is what you desire you may find yourself very frustrated.

Long version: Finding a well fitting PWK is no longer a struggle as Keihin now sells the PWK-AG (Air Guide) as an aftermarket carb. It is a 75mm short body and uses the same castings as the OEM YZ/RM/KX250 carb and bolts right onto the YZ125 and fits great. STIC sells the complete PWK-AG with the STIC system already installed and includes the new JD red and blue needles. I bought this setup direct from STIC for about $450.

I bought this back in October and have been trying to get it running correctly on my 2006 YZ125 ever since. Background - my bike runs absolutely flawless with the stock Mikuni and I've been jetting dirt bikes for 40 years and have a pretty good idea what I'm doing. Some factors to consider. George at STIC appears to be a 1 man show (or very small operation) and is getting up there in years. So, turn around time for parts and such can add to your experience. On the other hand, I have multiple bikes so I have not dedicated every second to tuning this thing and that has caused delay as well.

That being said, my experience is that George thinks the STIC and his settings are universal, bolt and go. I've found that to not be the case on the YZ125. At this point, I feel like I've essentially become the beta tester for putting this thing on a YZ125 and I may be the first to develop any real, reliable settings.

Without going into every gritty detail, suffice it to say I've had the subframe and carb on/off the bike probably 50+ times at this point. It was initially delivered with the .113A tube because George thought that would work on any bike. It bogged horribly even though I tried every pilot/main/needle combo imaginable. I sent it back to George and he corrected an out of place jet block o-ring. After that it was much better but I still could not get rid of the bog when whacking the throttle. George then developed the .114A tube and sent that to me. Again, closer, but still has the bog. I have not exhausted all pilot/main/needle combos with the .114 tube yet.

I'm persisting because I am hoping to see these awesome gains everyone talks about. I've had one person tell me they have a STIC running good on a YZ125 but it appears to be an earlier version with a .115 or .114 tube and a custom filed OEM needle. If anyone has one, no kidding, running awesome on a YZ125 and can share settings, I am all ears.
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Bruce372
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3/29/2020 7:12pm
FGR01 wrote:
TL/DR: Putting a PWK with STIC on a newer YZ125 is not a quick bolt and go proposition. If that is what you desire you may...
TL/DR: Putting a PWK with STIC on a newer YZ125 is not a quick bolt and go proposition. If that is what you desire you may find yourself very frustrated.

Long version: Finding a well fitting PWK is no longer a struggle as Keihin now sells the PWK-AG (Air Guide) as an aftermarket carb. It is a 75mm short body and uses the same castings as the OEM YZ/RM/KX250 carb and bolts right onto the YZ125 and fits great. STIC sells the complete PWK-AG with the STIC system already installed and includes the new JD red and blue needles. I bought this setup direct from STIC for about $450.

I bought this back in October and have been trying to get it running correctly on my 2006 YZ125 ever since. Background - my bike runs absolutely flawless with the stock Mikuni and I've been jetting dirt bikes for 40 years and have a pretty good idea what I'm doing. Some factors to consider. George at STIC appears to be a 1 man show (or very small operation) and is getting up there in years. So, turn around time for parts and such can add to your experience. On the other hand, I have multiple bikes so I have not dedicated every second to tuning this thing and that has caused delay as well.

That being said, my experience is that George thinks the STIC and his settings are universal, bolt and go. I've found that to not be the case on the YZ125. At this point, I feel like I've essentially become the beta tester for putting this thing on a YZ125 and I may be the first to develop any real, reliable settings.

Without going into every gritty detail, suffice it to say I've had the subframe and carb on/off the bike probably 50+ times at this point. It was initially delivered with the .113A tube because George thought that would work on any bike. It bogged horribly even though I tried every pilot/main/needle combo imaginable. I sent it back to George and he corrected an out of place jet block o-ring. After that it was much better but I still could not get rid of the bog when whacking the throttle. George then developed the .114A tube and sent that to me. Again, closer, but still has the bog. I have not exhausted all pilot/main/needle combos with the .114 tube yet.

I'm persisting because I am hoping to see these awesome gains everyone talks about. I've had one person tell me they have a STIC running good on a YZ125 but it appears to be an earlier version with a .115 or .114 tube and a custom filed OEM needle. If anyone has one, no kidding, running awesome on a YZ125 and can share settings, I am all ears.
Try the blue needle in the richest position, 52pulot and 205 main.

I am running that with the 113A tube, the only time I got that bog with this setting is 3red gear nearly at a stand still then wack the throttle
FGR01
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3/29/2020 8:32pm
Bruce372 wrote:
Try the blue needle in the richest position, 52pulot and 205 main. I am running that with the 113A tube, the only time I got that...
Try the blue needle in the richest position, 52pulot and 205 main.

I am running that with the 113A tube, the only time I got that bog with this setting is 3red gear nearly at a stand still then wack the throttle
Been there done that. Like I said, tried basically every conceivable combo of pilot/main/needle (and float position) with the 113A tube. I had to go blue-max and main up to 215 to even get close with the 113A tube. But it still had a bog that was bad enough that it was not safe to go on an MX track. Would rip just fine up and down the street and in the pits when rolling the throttle on smooth. But on the track sometimes you need it to respond when you whack it, like when there is a jump right out of a corner. I will accept absolutely zero bog because that is what I have with the Mikuni. I'm not looking to go backwards.
Bruce372
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3/29/2020 8:36pm
Bruce372 wrote:
Try the blue needle in the richest position, 52pulot and 205 main. I am running that with the 113A tube, the only time I got that...
Try the blue needle in the richest position, 52pulot and 205 main.

I am running that with the 113A tube, the only time I got that bog with this setting is 3red gear nearly at a stand still then wack the throttle
FGR01 wrote:
Been there done that. Like I said, tried basically every conceivable combo of pilot/main/needle (and float position) with the 113A tube. I had to go blue-max...
Been there done that. Like I said, tried basically every conceivable combo of pilot/main/needle (and float position) with the 113A tube. I had to go blue-max and main up to 215 to even get close with the 113A tube. But it still had a bog that was bad enough that it was not safe to go on an MX track. Would rip just fine up and down the street and in the pits when rolling the throttle on smooth. But on the track sometimes you need it to respond when you whack it, like when there is a jump right out of a corner. I will accept absolutely zero bog because that is what I have with the Mikuni. I'm not looking to go backwards.
i am with you! yeah, sucks to be the person to work it out.

ironically, it went best with the first plain 144 and yamaha needle LOL
dfree382
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11/30/2023 8:56pm

Has anyone gotten the yz125 dialed in with stic? Mine came with a yellow N3EJ needle in the 3rd position, 200 main, and 65 pilot. Ive switched to a 50 pilot, and the purple N3WJ needle in the 3rd position. Still not getting any better. (From what I’ve read online, the problem is related to the float not being set correctly) but from my understanding, I set the float correctly. My bike keeps bogging down off the faces of jumps, whenever I “G out” in bottoms of valleys (gravity cavities) backsides of rollers, or when I flat land. Pretty much any time my suspension compresses and I’m on the gas, it bogs out. I turned the idle up thinking that was related. Ive tried the two different needles that came with my kit. I’ve tried up and down all the way on both needles from richest to leanest positions. I’ve tried the fuel screw all the way out, I’ve tried the fuel screw almost all the way in. What could be causing this? I’m scared to hit any jumps on this bike now 🤦‍♂️ Also when it does bog and sends me off jumps like Ronny Mac, I can’t panic rev it back, the bike just cuts out and doesn’t have a clean panic rev

Bruce372
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11/30/2023 9:43pm

The first one I ever tried did that big on landings.... it was the float setting. 

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CPR
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12/1/2023 12:12am Edited Date/Time 12/1/2023 12:12am
Joko wrote:
Considering replacing the stock Mikuni on my 07YZ144 with a STIC Keihin 38mm airstryker to get more top end. Anyone have any experience with this application...
Considering replacing the stock Mikuni on my 07YZ144 with a STIC Keihin 38mm airstryker to get more top end. Anyone have any experience with this application? Did it make it make it more peaky with a narrower power spread?
It the STIC claim of 10% increase accurate? Thanks...

The standard Mikuni seems to much maligned by people who aren’t good at tuning, but if you get them jetted right, they’re absolutely sweet.
If you’re only looking to improve the top end, there’s plenty of better and easier options imo.

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Richy
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12/1/2023 12:45am

Can somebody educate me on this STIC thing?

It's still a carb, so how is it (when working correctly) so much better than a Mikuni (again when working correctly, so whether it means changing slide, jets, needle, etc for KTM or just screwdriver tweaks with a YZ) or regular Keihin?

FGR01
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12/1/2023 4:27am
Richy wrote:
Can somebody educate me on this STIC thing? It's still a carb, so how is it (when working correctly) so much better than a Mikuni (again...

Can somebody educate me on this STIC thing?

It's still a carb, so how is it (when working correctly) so much better than a Mikuni (again when working correctly, so whether it means changing slide, jets, needle, etc for KTM or just screwdriver tweaks with a YZ) or regular Keihin?

Look at the other thread that is recently resurrected and you'll see the STIC creator, George, is all over it with his infamous copy/pastes of walls of STIC info text.

https://www.vitalmx.com/forums/Tech-Help-Race-Shop,42/STIC-Metering-blo…

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Tim507
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12/1/2023 5:35am

On my 2022 YZ 134 I ordered a Lectron Billetron, it arrived, installed it and never looked back - man does this bike rip!

Also put the Billetron on my CR125 shifter kart, only had to make an adustment (1/2 turn richer) to the Power Jet as the kart runs without a Power Valve (removed) and it is well over 10K on the average all the time.

https://www.google.com/search?sca_esv=586971717&sxsrf=AM9HkKmyfRgbR9_88…Tongue z4JF-NSHho,st:0

 

dfree382
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12/3/2023 6:29am

I got the bog to go away, I blame the yellow N3EJ needle. I believe the bog was happening because the bike was too lean. I was just running the carb how George sent it to me because he said it would be good to go. Anyways, I switched to the richer, purple N3WJ needle, in the second position. Still running the 50 pilot, went to a 200 main

StillSmokin
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12/3/2023 7:42am

your pilot and main are too small imo. N3EJ is a super lean needle for a 125. The right combination of pilot to main jet is what needs to be achieved other wise STIC feels like a regular carb. JDjetting best dynos with n3ej needle came with a 215 main on the 300 ktm so a 125 is gonna need much richer which doesn't leave options. Did Stic send you a modified n3ej with the sanded tip?? If you just managed to tune the bog out you are probably still too lean to fully take advantage of the stic imo.

I would try 205, 210 and 215 mains. There will be a very large increase in power when you get the right ratio between pilot and main.

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Bruce372
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12/3/2023 10:35am

How come people are going back to the Yamaha needles.

Both my setups are the JD specific stic needles, they made blue, red and white

dfree382
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12/7/2023 8:48pm
Bruce372 wrote:

How come people are going back to the Yamaha needles.

Both my setups are the JD specific stic needles, they made blue, red and white

Idk but these are the two needles George sent me. The N3EJ was inside the carb when it arrived. I am now running 55 pilot, 205 main, purple N3WJ. I was talking with Derek at hp performance and he said I could also try running the stock mikuni needle (6BFY43-74). None of my needles are sanded flat, but I thought about trying that out as well. I will be trying to 210 main, and the 6BFY43-74 needle this weekend, keeping the 55 pilot

FGR01
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12/8/2023 7:41am

Mikuni needle in a Keihin with a STIC ???    Wow.

racerxx276
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12/8/2023 9:16am

So I recently installed george's complete stic carb . I'm not talking the insert.

Its jets much easier than the insert. Best running 2 stroke I have ever owned and I've been racing them for 50 years...

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Joko
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12/8/2023 8:15pm
racerxx276 wrote:
So I recently installed george's complete stic carb . I'm not talking the insert. Its jets much easier than the insert. Best running 2 stroke I...

So I recently installed george's complete stic carb . I'm not talking the insert.

Its jets much easier than the insert. Best running 2 stroke I have ever owned and I've been racing them for 50 years...

Can you describe how it runs better? Is there any substantial power increase you noticed? Thanks!

Bruce372
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12/8/2023 9:51pm
FGR01 wrote:

Mikuni needle in a Keihin with a STIC ???    Wow.

 Belive it or not, some people tried it and it worked well. It's risky tho since it's not perfect fit and it sits slightly loose

racerxx276
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12/9/2023 5:22am
racerxx276 wrote:
So I recently installed george's complete stic carb . I'm not talking the insert. Its jets much easier than the insert. Best running 2 stroke I...

So I recently installed george's complete stic carb . I'm not talking the insert.

Its jets much easier than the insert. Best running 2 stroke I have ever owned and I've been racing them for 50 years...

Joko wrote:

Can you describe how it runs better? Is there any substantial power increase you noticed? Thanks!

Major power increase. The older stic insert never really offered more low end, but the new stic carb is a powerhouse. And I mean it's not hard to handle but

Very smooth. Everyone that has ridden my 19 300xc wants one!

1
jpred
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12/11/2023 6:05am
racerxx276 wrote:
So I recently installed george's complete stic carb . I'm not talking the insert. Its jets much easier than the insert. Best running 2 stroke I...

So I recently installed george's complete stic carb . I'm not talking the insert.

Its jets much easier than the insert. Best running 2 stroke I have ever owned and I've been racing them for 50 years...

Joko wrote:

Can you describe how it runs better? Is there any substantial power increase you noticed? Thanks!

racerxx276 wrote:
Major power increase. The older stic insert never really offered more low end, but the new stic carb is a powerhouse. And I mean it's not...

Major power increase. The older stic insert never really offered more low end, but the new stic carb is a powerhouse. And I mean it's not hard to handle but

Very smooth. Everyone that has ridden my 19 300xc wants one!

Do you have to purchase that carb directly from George?  I have the insert now and it added quite a bit mid to top.  The complete carb is interesting....

racerxx276
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12/14/2023 3:25pm

yes, got it from george. The new carb will add low which the insert didn't And of course much more mid to top over the insert.

 

Very impressed with it.

1
12/14/2023 5:49pm

How is the overall quality of the Chinese Keihin clone with the insert? Is it any better or worse than a real Keihin? Sounds like the performance is there.

TDC
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12/14/2023 7:55pm Edited Date/Time 12/14/2023 8:29pm
racerxx276 wrote:
yes, got it from george. The new carb will add low which the insert didn't And of course much more mid to top over the insert...

yes, got it from george. The new carb will add low which the insert didn't And of course much more mid to top over the insert.

 

Very impressed with it.

Good to see some Super X carb feedback. I've been having a back and forth with a guy over on TT that says the STIC products reek of corner store energy pills and late night commercial claims. He also really didn't like that I stated that the carb body is cast in Cali., that's what I was told anyways.

Did your carb casting also appear to be of high quality? 

 

BTW, from the way my 200SX w/the 115t/insert ran, I ordered the G2 throttle cam system for my Super X carb. I use the slowest turn cam for the track! It returns the throttle to a more regulated std carb range.

N3WJ @1 clip_#7 slide,_80p_100acj_200m_AS 2 out.

TDC
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12/14/2023 8:14pm
racerxx276 wrote:
Major power increase. The older stic insert never really offered more low end, but the new stic carb is a powerhouse. And I mean it's not...

Major power increase. The older stic insert never really offered more low end, but the new stic carb is a powerhouse. And I mean it's not hard to handle but

Very smooth. Everyone that has ridden my 19 300xc wants one!

My 200SX is so abrupt with a 115 tube and Super X carb that my arms ache for days after a track day. I get nothing like that from my '24 300SX. Ppl that ride the 2hun are spooked and wonder how I ride it. I think the STIC stuff is magic on smaller bores.

TDC
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12/16/2023 11:40am Edited Date/Time 12/16/2023 11:48am
How is the overall quality of the Chinese Keihin clone with the insert? Is it any better or worse than a real Keihin? Sounds like the...

How is the overall quality of the Chinese Keihin clone with the insert? Is it any better or worse than a real Keihin? Sounds like the performance is there.

The quality on mine is quite high compared to a Chinese clone I have. It looks like a PWK, but it has internal differences. BTW, not sure why you say it's a Chinese clone. I've been told differently.

Regardless, it is much better than a Keihin, if you seek every aspect of the powerband to be at a high performance level, especially dramatic for smaller bores.

I'd say it would be worse than, if you can't or don't want to manage it's intensity. My forearms ache for days after a track day, but I love the YAT for my 200lbs..

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