2016 KTM 125sx carb on 2017 KTM 125sx?

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7/25/2017 7:41 PM

Has anyone switched out their 2017 KTM 125sx Micrapi carb for the stock Keihin carb from a 2016 bike? Just wondering what parts (other than the carb) is required for the swap? Intake boot? Throttle cable? Air filter boot?
And what years of Keihin carb would be compatible?



7/26/2017 1:55 AM

Purely based on browsing ktm sparepartsfinder web site (it uses * marking next to part numbers which are new that year) it looks like just the intake flange, its clamp and throttle cable has changed. Also in the handlebar end of the cable the "throttle body cpl" has new part number but perhaps for different reasons? The carb itself has the exact same part number 2014-2016 but I think even earlier ones are almost same.


7/26/2017 4:45 AM

exbmxmx wrote:

Has anyone switched out their 2017 KTM 125sx Micrapi carb for the stock Keihin carb from a 2016 bike? Just wondering what ...more

I love the Mikuni on my TC250. What's wrong with yours?


7/26/2017 7:42 AM

Thanks Zeikei! I had no idea about that spareparts finder feature. Very useful.

Erik, We have had trouble keeping a consistent tune with the mikuni. Like for example, after getting the bike running right during the daytime, we showed up for a night practice and the bike was bogging really bad on corner exit. Granted the Houston humidity was in full effect that night but damn it required a 2-position clip needle change to get it back to good.
Just looking for something to help. Thought the 16' carb/jetting were already worked out and so I thought it might be an easier solution to change the carb to the 16' model setup.

Thanks for the help.


7/26/2017 9:00 AM

The easiest thing to do would be to spring for a JD jetting kit. I was very skeptical at first and spent a fair amount of time decoding needles and the like. I got it pretty good on my own after several rides. The JD kit is better, especially if you want to shortcut the process.

Here is a thread I made on TT about the TMX: https://thumpertalk.com/forums/topic/1224849-mikuni-tmx-needle-decoding/

And I see a bunch of threads on KTMTalk about the TMX jetting.

Before doing anything, I would highly recommend checking your float level and make sure your reeds are sealing. My float was off and my reeds had gaps. Fixing both helped the low end on my 250.


7/26/2017 10:23 AM

Thanks for the info...

Already have the JD kit installed along with new Moto Vforce4 reeds.

I just ordered a leaner idle jet and when I install it, I will recheck float height but I set it when I originally installed the JD kit.

Another piece of the puzzle was on the same night that we had the bog, we had just replaced the clutch. So possibly the clutch was slipping just enough to cover up our jetting problem on the past rides? Idk.

The boy won on it Saturday night so it seems to be getting close but he says its still has a slight bog. So I was thinking about trying the 16' carb to see if we have some better luck.


7/26/2017 6:46 PM

The PWK is definitely more set it and forget it. My 2014 150SX is very solid/stable. The TMX makes more power though. I actually bought a TMX to put on it eventually.


7/26/2017 9:20 PM

Anyone have some good 2016 carb settings they can share. I'm going to try the OEM carb back to back with the Lectron. Not sure if either are set up right perfect...


7/27/2017 2:40 PM


I was planning on starting with the JD jetting kit. Surely after all those years with the PWK carb they should have a good baseline developed.


7/27/2017 6:54 PM

If I recall correctly MXA went from a 42.5 pilot jet (stock) down to a 25 to get it to run correctly. That should give you some idea of how far off the stock jetting is.


21.5 350 XC-F
96' XR600r