2021 Ktm 125sx carb or jetting recommendations

The above cutaway block pic shows the shorter pilot and a threaded plug to the fuel bowl. Between the two you see a rod exhibiting the X passage connecting the pilot chamber to the main jet tube, just above the main jet. 

Below you can see the air correction jet at the lower intake bell. When the pilot reverses flow, this is one of and the largest of the air/fuel vapor accumulation sources.

So its still a pwk carb, but more extensively modified?

It's a clone, externally. Cast in Cali., so, made in the US of A!

On my 17 the slide was too rich. Cut it to 6.5, jd needle and block jet gasket, 45 pilot and ? on the main. Also float level was way to high. Must have been some drunken employees who set up the Mikunis on the 17's. If you want more torque for trail riding, put a splitter in the engine side of the slide and go with the SX insert on the head that Langston sells.

That insert wing in the carb bore really helps dial in a pilot circuit. It makes the signal stronger and will transition stronger from low rpm under loads to whacking WFO. 

2022 125sx stock carb. 

Whoever tuned Jimmy DeCotis 125SX must be a Jedi master or a jetting master.  Listen to his video of the race in Canada.  

Imma wondering if he runs any STIC products. I've read that Steinke ran the metering block. You don't even have to worry about if you shift too early, bc there's no longer that narrow bubble. That classic mid hit gets placed a bit above idle. I can't even get a laggy pilot jet throttle response on my 200SX and I use the slowest turn G2 throttle tamer. A few buddies have commented about how sick the sound is. I moved up to the Super X carb and on the 2nd ride, I think it caused the PC 304 arse end to blow out at the end cap weld!

TLR (Todd Lachance) in Florida did the engine for Jimmy and he runs the mikuni.

Perhaps more tuners will adopt the STIC technology.

I mentioned how potent my STIC was to a tuner that did my suspension. It didn't phase him when I wanted his last 198 main jet for my 200SX. He was surprised he had one and stated that no one uses anything that big. I mentioned I'm using a 200 main and 80 pilot, not a 45/175. Some of these guys don't listen well or take in any new information. Well, same goes for riders, eh.

Video of your bike in action, please.   With special emphasis on sound.

I'd like to oblige, but I've never... Well, lets see if I remember and have someone capture it 'on the pipe'.

Had a guy with a GoPro get some laps for me today. I'll post once he gets the clip to me. 220 lbs 6'4" fit young buck. He pulled in and said wow wow wow, I think it's faster than my fresh rebuilt '98 KX250.

Which company, STIC or HP?

The Super X carb, I believe is only available thru. STIC. 

Be sure to have healthy reeds as well.

Have you tried switching the carbs between the bikes? 

Yep the manufacturing tolerance on these bikes aren't exactly what we should be getting for what we pay Squish and compression aren't always the same!

What are your current settings, BTW? Everything that is.

Were the Super X carbs ordered/received at the same time?   George has been updating/changing X passage, needle jet tube, air correction and pilot sizing. As he tries to finalize specs.

Updated (October 2024) “X” tuning for the 250/300

The New STIC (New Keihin) Super “X” jetting (new specs) delivers a convincing superior linear feeling with better throttle control and greater power than the regular STIC. 

These carburetors come pre-jetted, with a typical 300 set up with the following specifications:

Number 8 block

Number 6.5 slide

Number 50 “X” pilot

Number 100 Air correction jet

Number 190 main

Air screw 2 ½ turns

Yellow needle 4th clip

Slide dry setting .020”

The new slide adjustment screw is 5mm X 30 torx 20/25 and is thread locked with Teflon tape.

This “X” comes with a jet kit including three needles: White, Yellow, and Red, with extra jets, 200, 195, and 180, with a full set of instructions, allowing one to jet a 125 through 500cc. For a very clean low end, we recommend you start with a 32:1 oil/fuel ratio, working down to 28:1.

This setup is exceptional in performance. 

The STIC and STIC “X” have an additional auxiliary fuel source.

The STIC power jet features were planned from the beginning of 2012, and 2014. The 7D power fuel passage was implemented (manufactured) before the STIC Super “X” was incorporated. The 7D power fuel passage remained dormant for the first four years of the STIC operating system. The “X” was finally incorporated in July 2024, which activated the dormant 7D power fuel passage.

The STIC has had an additional auxiliary fuel source from the beginning; now that the “X” has been implemented, it is activated and supplements the main jet power system. The pilot jet cavity that houses the pilot jet has an additional fuel source, and the STIC block’s main body has an auxiliary passage, BNG-07D, that provides a continuous auxiliary source of fuel to the main jet tube. This BNG-07D passage is located on the printed side of the block directly below the side check ball and directly below the “S” on the acronym “USA.” This BNG-07D auxiliary fuel source entrance is approximately one inch below the wet fuel surface. The lower cavity just below the pilot jet is in a low-pressure area due to pressure and speed flowing through the lower pilot jet in both directions, low pressure is created by shearing pressure drop and the displacement rule.

 The engine’s high-speed air and pressure flow emanates from the BNG-05C frontal engine airspeed air correction jet. This speed and pressure travel to the BNG-06’s lower cross-over BNG-04D/BNG-01D passage, which creates a shearing pressure drop within the lower pilot jet cavity. This low-pressure area is conducive to pulling fuel from the float bowl cavity via the BNG-07D passage leading into the pilot jet’s lower cavity. This happens continuously as atmospheric pressure of 14.7 psi at sea level, (not considering any weather or altitude influences) acting on the float bowl fuel surface pushes the fuel toward the pilot jet's lower cavity. This BNG-07D passage provides a continuous fuel source that automatically maintains a full fuel level in the lower part of the pilot jet cavity. This fuel inlet passage is depicted in the WO patent overlay.

This flow to the lower pilot jet cavity from the BNG-07D passage connects the float bowl fuel source to the pilot jet’s lower cavity. This flow through the BNG-07D is super-enhanced as the engine’s airspeed is directed into the BNG-04D/BNG-01D of the BNG-06 tube’s lower passage. 

The high-speed flow from the BNG-05C frontal air jet passes through the pilot jet's lower cavity and into the BNG-04D/BNG-01D passage, removing the fuel from the pilot jet's lower cavity. However, the displaced (utilized) fuel is replenished with a continuous source from the float bowl. As the float bowl fuel level drops (consumed) below the BNG-07D’s lower entrance point, the BNG-07 will start to consume the atmospheric air pressure above the float bowl fuel level, thus keeping the engine from running rich in the higher rpm range.

 The BNG-07D additional auxiliary fuel source is not to be confused with the BNG-09 acceleration cavity. The BNG-07D additional auxiliary fuel source supplements the main jet when the BNG-04D/BNG-01D supplies a rush of additional engine air and pressure from the BNG-05C air correction jet that supplies additional air, pressure, and speed from the engine.

Here is the new BNG-07D STIC Super "X" power fuel supply passage that remained dormant for four years while we were planning on the upgrade to the STIC Super "X."  It has now been activated (July 2024). You can trust the words of TDC as he has the latest, and he is honest, a trusted friend who is unbiased!

What happened to this? Interested on getting the Stic for my Cr250, can't seem to find any way to order it online.

Direct from STIC

vortex@sticfuel.us