The Best 125 Duke Airbox Power Mods

[@yappingf1original]

Loverd the video! You requested that we chase you up to do a video of the cutting of the airbox tube... this is me chasing you up 😛 would love to see that vid. Thanks!

[@Ss-jx2eo]

Will you do a video on cutting the airbox tube on a 125?? I really want to see how to do it

[@MotoMirius]

That is the plan. Chase me up if you don't see it.

[@pesuaine-3817]

@@MotoMirius video about cutting the airbox tube on the 125 duke would be definetly nice

[@crowboy9818]

Here's another 125 owner.. waiting for that video of you cutting the outlet tube 😂

[@RhoadsChristopher]

Great idea cross platform modifying like that. That is a huge difference in size! Question, how does the 390 throttle body compare to the 125? Also, will you have a follow on running that air box?

[@MotoMirius]

Throttle body is also much larger on the 390. I can't quite justify buying a throttle body just to show the size difference between the 125 and the 390 but if I see one cheap enough I might. I already run an airbox with a modified intake runner. I guess I should do a video of my current setup.

[@rajsaroj4696]

amazing videos, i've installed dual disc front brakes and now i was thinking of installing a supercharger in my ktm rc. Can you make a video on possibility of how it can be solved ?

[@MotoMirius]

Thanks. Outside of the drag strip, superchargers are almost never found because of the difficulty in installation. Road bikes almost always go the turbo route because it is easier to install. Don't think I've seen anyone do this with an RC for years - much of its speed comes from its agility so adding weight can be counter productive. But good luck with your project!

[@loch5604]

Love your videos! Keep up the good work :) I also wondered if are thinking on making a video on how to modify the 125 airbox? And will shorterning the airtube on the 125 airbox, need a different fuelinjector? (more fuel)

[@MotoMirius]

I am planning on doing a simple video on the airtube. Yes, I think it would be reasonable to expect a bigger injector - fortunately you have the immediate options from the larger small Dukes. I've not tried them but I would think there is a reasonable chance they will fit.

[@loch5604]

@@MotoMirius Thank you for your reply :) So useing the fuelinjectorsystem from the duke 200 and shorterning the airtube, will give the duke 125 more power?

[@MotoMirius]

@@loch5604 Ha! Well the thing you have to bear in mind is that it is a 125. A 10% increase in power would be a strong improvement - but it would only be a 137. So bear in mind that increasing the power of a 125 is a labour of love not logic. Given there are bigger engines with the same frame, the logical route is to swap out to a bigger version of the small Duke and invest the time and money into making that happen instead - this is very different from suggesting a bigger bike because they are also heavier etc.

[@loch5604]

@@MotoMirius Ah, ok :) Yeah, I'll probably just keep my duke mostly stock then🙃

[@loch5604]

Thank you so much for your detailed replyes🙂

[@tinks43]

Can clearly see the additional width. Enjoy your weekend.

[@MotoMirius]

Thanks, you too! Weather is looking good for Sunday - now I've jinxed it!

[@tinks43]

@@MotoMirius enjoy. I’m round Mother’s & need to fix the bike ready for March.

[@MotoMirius]

@@tinks43 thanks, well, I look forward to seeing you in March and thanks for doing that

[@wanshaneleazerdiengdoh284]

Hey....since ive seen ur vid on installation of the Fuel x pro......i was wondering if it was possible to install both the Powertronic V4 (ecu) and the fuel X pro....or is that not possible?...i own a 2017 390 Duke...and yea ur vids have made me a lil less afraid of tinkering with it....great vids

[@MotoMirius]

Hi, I have not seen the V4 yet - the FuelX was designed to work with the V3. But the V4 wiring harness does not appear to have the Lambda connector so it should also worth with the FuelX - which is what I would expect from the way the units are designed.

[@wanshaneleazerdiengdoh284]

Great Thanks 👍

[@torevenheim9607]

You can clearly see 390 box has a bigger intake aswell as outlet

[@MotoMirius]

Not true - the same gasket is used to connect the same air inlet tube on both the 390 and the 125 - same parts, same size

[@seenthroughvisor4579]

Hey I have a doubt Can a duke 250 be converted into 390 by swaping the engine components? Does the ecu and harness of 250 supports this swap Can you please let me know You are awesome

[@MotoMirius]

250 and 390 are similar engines but you will need the fuel and air systems from the 390 so I think you will also need the electronics and maps from the 390 otherwise it will not provide enough fuel.

[@seenthroughvisor4579]

@@MotoMirius thank you so so much❤️

[@nspirecustomdesigns2700]

Solid advice thanks

[@MotoMirius]

Thanks, you are very welcome

[@ManfredJobst]

where do I have to cut the hose

[@sarahtrueman9406]

Hi there i have a problem with my ktm125 duke it starts 1st time runs normal until it starts to get warm i hear like a electric ticking and the revs drop and keeps doing it till it dies

[@MotoMirius]

Hi, this isn't something you can really diagnose over the internet. Possibly an issue with your fuel pump. Good luck with that.

[@tsamokingn6599]

Hey sir, is it possible to change duke 200 throttle body to duke 125? (Not the Sensor) Only the body?

[@MotoMirius]

Anything is possible so long as the operating systems are compatible but I without checking I would also expect to need to change everything from airbox to engine not just the throttle body.

[@zigakos8837]

If i would do that to my ktm duke 125 with euro 5 eingen and a de cat with a slip-on exuste would the fuel x lite be enough? And would i see any power incres?

[@MotoMirius]

The reality of the 125 is that even if you increased the power by 10% - which is a lot on any engine, it will not make a big difference. Unless you can only ride a 125, say because of your age, then the most cost effective route is to sell it and buy a 390 which has 3x the power but is the same bike. Some people put a 390 engine in the 125 but this is a lot of work and the legality can be an issue. But yes, the FuelX Lite would be enough.

[@zigakos8837]

@@MotoMirius tnx for the feedback. For now i have only a drirvers licens for 125 . I just want to encrese a litle bit of tourq because im a little bit havyer and im gona get a 13 t front sprocket and a 45t rear.

[@oliverklinckmann1490]

Can You say what about oel in Airbox? My Duke 125 Model 2022 / 993km, Greet from Berlin Germany

[@MotoMirius]

Do you mean oil? This is normal on any modern engine where oil is not allowed to be dripped onto the road, so breather pipes are fed into airbox to allow for combustion of oil mist.

[@oliverklinckmann1490]

@@MotoMirius Many thanks for the Answer. Today I removed 50cc/ml Oil from the Airbox. I rode the Bike just 993 km. I'm looking for a Solution. The Oil should not remain in the Airfilterbox. Does the Engine use more Oil? Maybe an Idea for a new Video for you?

[@matiasmendez6174]

hello sir, im a ktm rc 390 2020 owner from Italy, i really like your videos and enjoy them while modifing my bike but i met and issue, when i start the engine cold i hear some grinding noise..i suppose is from the starter motor but i dont know... maybe its the battery. and now after winter came the engine stalls when cold then after the second start it goes well, maybe the spark plug? it has 9000km i cant find the answer anywhere please help me ç_ç.

[@MotoMirius]

Glad you like them! It is normal for the bike not to start first time when it is cold - sometimes takes two or three times to start depending how cold it is. Some grinding noise isn't normal, but if you only hear it when starting then yes, probably the starter motor. It may not be disengaging when the engine starts - this may also be a reason for not starting first time when it is cold. Starter motor should be checked.

[@matiasmendez6174]

@@MotoMirius thank you so much!!, ah i forgot to mention that the bike starts fine when cold but stalls..i hear that i doesnt hold low rpm when cold, i changed air filter with dna biker and exhaust, should i buy the fuelx lite that u recommended to fix this?

[@MotoMirius]

@@matiasmendez6174 If you've changed slip on and air filter then yes, I'd recommend thinking about a piggyback. Which one depends mostly on what you intend doing with the bike. The FuelX Lite is good for basic modifications, but if you want or expect to do more more mods then a more advanced piggyback is recommended - my preference then is the Italian RapidBike range.

[@matiasmendez6174]

@@MotoMirius thank u so muchhh!!!

[@TAZRI40100]

Il faut faire une nouvelle tulipe d'admission comme je l'ai fait

[@MotoMirius]

Do you have a link to buying one?

[@TAZRI40100]

@@MotoMirius fabrication maison

[@TAZRI40100]

J'ai mis les photo sur votre instagram

[@Thevoiceofsense]

In other words..... cut the runner in half to improve?

[@MotoMirius]

In very simple terms yes ;) I need to find the time to check my own runner to confirm dimensions.

[@Thevoiceofsense]

@Moto Mirius I noticed how you seemed pensive to say, as though it might somehow backfire on you haha

[@MotoMirius]

@@Thevoiceofsense Ha! No, it's simply that off the top of my head I can't remember how much mine is shortened, and I don't know anyone who has done the dyno work on say a 125 to get the optimal length. On some airboxes there is no runner at all, so that is also an option.

[@Thevoiceofsense]

@@MotoMirius ah that explains it haha don't blame you then!!