KTM RC 390 Part 3 (Coober headers, Fuel x lite, K&N filter, DNA cover, carbon fiber slip on)

[@gregharris2928]

2 yrs after this video was produced, is still relevant for me today as I plan on purchasing one this month and making these mods.

[@SeanFillner]

Glad you're still finding it useful!

[@benreed3939]

Just picked up a 23 model,really impressed for what you get for the $

[@dadontwo-wheels8202]

Not sure if your stock exhaust recording was the best recording... BUT, loved the new non-baffled sound of that exhaust. Gotta have fun sometimes and be loud.

[@SeanFillner]

The sound recording on these cameras really does it no justice. Not the same as in person...

[@donaldhalls2189]

I recon the new muffler is better, the more noise it makes the more you are noticed, the less likely car's will miss seeing you, all the best to you and your loved ones

[@madmac5709]

good video with all the necessary upgrades for the RC 390I did them all except for exhaust header, the fuelx was easy to install. I didn’t route the wires like you did but they are not visible on my install, Definitely noticed an improvement with fuelx! thanks for the great video. All the best to you 🎉

[@SeanFillner]

I am glad the videos helped you. Thanks for tuning in! Happy riding!

[@timothyrutledge1021]

Did you notice any power gains?

[@moayedf8247]

I wish if you showed how you changed the air filter cuz I’m planning to change mine and wondering if you have a video doing that.

[@SeanFillner]

Check the svartpilen build series playlist. Super easy.

[@MikeyCandela]

Was there any increase in power to the bike after all set and done?

[@SeanFillner]

You're funny!

[@MikeyCandela]

@@SeanFillner Really? Nothing?

[@SeanFillner]

@MikeyCandela "said and done". You already know the answer.

[@ECLATAX]

Almost 10k subs !!! Keep it up.

[@SeanFillner]

Trying to get there! Thanks for the comment!

[@Midex74driver]

Aftermarket exhaust sounds good. Just put the DB killer back on…

[@michaelschlup8610]

Hi I'm riding 2019 rc390 with power commander kit, gpr exhaust system and dna air filter. It's a blast.

[@SeanFillner]

Nice 👍

[@swift6776]

a couple questions: does the fuel x work on the 2024 rc390?? is there any actualy preformance gain? can i gain even more from a tune after instalation of all this stuff? also where can i buy the header, the ebay link is gone

[@SeanFillner]

I don't have any 2024 373cc powered bikes anymore.

[@33vialli]

Hi is the front paddock stand a genuine KTM stand?

[@SeanFillner]

Yes. Husky makes them. Check out my svartpilen build series playlist to see part numbers.

[@benmclaren3809]

If i was to buy the coober headers would i need to buy the fuel X or a fuel management system or would the stock ecu be enough for headers?

[@SeanFillner]

You can if you want. Not many gains to be made on such a low hp engine.

[@benmclaren3809]

Okay thank you!!!!!!!​@SeanFillner

[@jeffcunningham678]

Gonna be adding the Coober to my 390 Duke next week. It looks like you kept on the OEM chamber? Did the OEM header come off easily enough with the chamber in place? Thanks much

[@SeanFillner]

I covered the header replacement in this build series playlist...is there something i missed??

[@RemboUSMC]

it is hard to believe the difference in sound, even with the big cat still in place.

[@SeanFillner]

There isn't a cat on this system. That is a resonator and it is silly to remove it as it is your only source of any backpressure on these 373cc ktm motors.

[@El_Rudo]

@@SeanFillner the pre-muffler/resonator doesn't provide any back pressure - it is just an elbow with a big space lined with sound deadening material in it. The cat, which you removed, and the DB killer is about the only thing that provides back pressure in this system, and even then not much...besides, back pressure is a myth, you want the exhaust to flow out of the engine as freely as possible. The only time it is a problem is if you are running too lean, then you might scorch the valves. I been building motorcycle engines for 30 years and all the ones that can "breath" good have much cleaner valves and cylinder head.

[@SeanFillner]

@@El_Rudo thanks for sharing that information.

[@El_Rudo]

@@SeanFillner So here is s bit more information: What most people think of as "back pressure" they usually mean the negative pressure wave or harmonic scavenging that is caused by baffles in the exhaust system. Baffles can be anything from the cat, 90 degree turns in the exhaust system, butterfly valves, or the DB killer. Think of it as a sound wave more than exhaust gas pressure. True back pressure is mostly caused by too narrow an exhaust diameter or restrictions in the exhaust system, and is strictly speaking gas pressure. If all the exhaust gas is not evacuated from the cylinder, to allow optimum space for fresh cool gasoline enriched air in (which has a cooling effect), and the piston has to work to push the exhaust gas out on the upstroke due to restrictions in the exhaust, you lose HP and your valves and cylinder head will run hot. In an exhaust system you want velocity in the motion of the exhaust gas from the exhaust valve to the tip of the muffler. Velocity helps extract exhaust gas out of the cylinder and keep things flowing, along with the negative pressure wave/harmonic scavenging (more on this later). If you have too narrow diameter an exhaust header this will cause true back pressure. Too wide a diameter and you lose velocity. The negative pressure wave or harmonic scavenging works by a sound wave that is caused by a baffle in the exhaust to rebound back to the exhaust valve just in time as it opens to help create a negative pressure "space" just as the valve opens so that the positively pressurized exhaust gas will escape more quickly in to the negative pressure "space" and help create the needed velocity. This however only works at certain, usually lower, RPMs. Usually people equate this with torque, and why they say if you lose back pressure you lose torque on the low end, or that the engine idles rough (rough idling is usually caused moreso by too wide a diameter exhaust header pipe). This negative pressure wave also pays more dividends the more cylinders your engine has. This is because as one cylinder has expelled it's gas and the exhaust valve is closed you want the negative pressure wave at the front door of the next exhaust valve just as it opens to maintain the exhaust velocity to keep things flowing. The other reason you would want the negative pressure wave is if your engine has a lot of valve timing overlap. The overlap is the amount of time when your intake and exhaust valves are both partially open. If the negative pressure wave is timed right for valves that have a lot of overlap it can help draw in cool air (before the injector sprays gas into the intake air) from the intake side to help evacuate the exhaust gases from the cylinder head and help cool things down. I am not 100% sure, as I haven't looked at the valve timings, but with the 390/373 engine being a high compression engine I don't think the valve timing overlap is huge in this engine. Also, with it being a single cylinder engine you get further diminished returns from the negative pressure wave. I think the cat helps with the negative pressure wave at low RPMs, probably part of the reason the bike is so jerky/torquey at low RPMs, and the DB killer helps at high RPMs, this may be part of the reason for the dead spot for torque in the midrange. From my examination of the exhaust, as long as you don't shorten, narrow, or widen the header pipe, have a proper DB killer on the muffler, and don't run too lean by way of using a good fuel controller (especially if you delete the cat) you should be fine. If you are running too rich and you have deleted the cat this will cause backfiring, especially during engine braking. This is why it is best to have an active fuel and ignition management system if you delete the cat, or at least one where you can control the richness, like the Fuelx Pro. Deleting the cat, and the possibly the pre-muffler, will probably help smooth out the power curve on the 390/373. A higher end DB killer will give you the negative pressure wave to help at some RPM range, different manufacturers like Akrapovic or Leo Vince will probably affect different RPM ranges, but again, probably not by much on this engine. I say it is the length and the diameter of the exhaust header that is important on this engine because after the exhaust header on the stock bike is the pre-muffler, which has a big widened space that causes a sudden drop in velocity. The other reason is because the Akrapovic exhaust that KTM/Husqvarna sells for the Svartpilen is much shorter than the stock exhaust, so total exhaust system length after the header pipe is probably not that important. This is a single cylinder engine, so not a whole lot of tweaking you can do to try and get the perfect amount and timing of the negative pressure wave. These are my observations based on my experience. I provide no warranty or responsibility for any of the statements or suggestions made here. Use this information at your own risk, peril, or possible detonation of your engine.

[@The.JZA.]

Sounds like something is rattling?

[@SeanFillner]

It's probably my brain. I have a few loose wires up there...

[@jakebsellin]

Do you have to wait this long on every start after adding the FuelX or just after the initial start?

[@SeanFillner]

Initial...

[@MichaelMoreno-ip4go]

I just stumbled upon your channel and still learning what additions you've done to the RC390 and others but I wanted to know, after a few months now, how do you feel these have improved the bike? Just researching the fuelx, did that provide lower temps and responsiveness...? What about the filters? Was that a noticable change when you filmed this? I am totally new and did get an rc390 a little bit ago, which as I said I just stumbled upon your channel, but dont entirely have tons of time to watch the video in its entirety yet, respectfully

[@SeanFillner]

I am sure, I have no doubt, you will find that time.... Thanks for tuning in!!

[@Hkmmotologs]

Hi, I have a doubt regarding the DNA airbox lid, does water enter to or through the air lid when rode in heavy rain, water crossings or when washing the bike using pressure washer?.. I have booked 390 Adv and planning to do the air filter and lid upgrade with fuel X pro(only) without additional ECU, just stock. No exhaust mods planned because of strict legal issues for altering exhaust here and regular checking so not worth experimenting. I was plannig to run fuel X pro on map 5 to 7 to compensate for the extra air with the upgraded filter and lid. what's your experience?

[@SeanFillner]

You don't need the pro. Get the fuel x lite. Even with the oem air box lid on all of your fears would be the same. It is not a 100% waterproof sealed system. You will be fine.

[@Hkmmotologs]

@@SeanFillner Thank you for your suggestion :).. I am from south India and here 60%of the year is rainy season and I usually wash my bike using a home pressure washer. that's why I was curious about the top airflow lid :). In sketchy situations I will just take some precautions to avoid water getting in :)

[@timothyrutledge1021]

Great video fellow Oregonian 🎉 how much power did all the upgrades add? I’m looking at doing the same to my 2023 RC390

[@SeanFillner]

Not much if I were to guess.

[@donaldhalls2189]

It sounds pathetic with the standard muffler, sorry, I think you should try the new resonator, thanks for showing, all the best to you and your loved ones

[@juniorgarcia8869]

How long did it take to get the fuelx lite ship to you

[@SeanFillner]

I ordered 4 at once. Took 5 days IIRC.

[@AlexTerwillegar-qr2bk]

I'm looking for that link...

[@SeanFillner]

Always in the description IF I found them in stock...

[@User_Brandon]

I see you got quite the husqvarna/ktm collection. In regards to the Husq 401/RC 390, those little 373cc engines are a lot of fun indeed. How have yours been for reliability?

[@SeanFillner]

All 5 bikes 0 issues.

[@User_Brandon]

@@SeanFillner I'm curious about getting an RC 390 myself, I got some questions. Do you do all the service yourself? Did you obey the break in periods to a T? What kind of mileage do they have and do you always use the recommended fluids?

[@SeanFillner]

@@User_Brandon check out the build series playlists I have created for each motorcycle to see the answers to all of your questions. Thanks for tuning in!

[@theodorechiu6875]

is there room to put in the header without removing the rad?

[@SeanFillner]

Did you watch the video? Apparently not.

[@theodorechiu6875]

@@SeanFillner You just showed the new header on... zero mention of moving the rad and the clearance looks tight. Yes I watched the video but clearly it wasn't as helpful as you thought cuz I still had a question that you still haven't answered

[@SeanFillner]

@Theodore Chiu I covered this header install on 3 bikes all with the same motor. Check out the svartpilen build playlist if you want to see a time-lapse of what it takes to install one.

[@theodorechiu6875]

@@SeanFillner Thanks, but a simple yes or no would have sufficed, it was unnecessary to be an absolutely insufferable cretin. Also just because the motors are the same doesn't mean the rest of the bike is. The rad location and frame are all different (among other things).

[@SeanFillner]

@Theodore Chiu if you watch the other videos you will see I proved you wrong. The installs are exactly the same on all 3 bikes. Not one bit of difference. Take care!

[@laundrieshanging9077]

Freak that decat isn’t available anymore haha damnit!

[@SeanFillner]

When I post a link they sell out fast.

[@laundrieshanging9077]

@@SeanFillner you arent wrong! haha. im thinking about getting a fuel x pro and exhaust for my 390 adv- you think those will work well together?

[@SeanFillner]

@@laundrieshanging9077 check out my 390 adventure build series playlist...

[@leanit5756]

14:03 that's what she said.

[@johnhannah9163]

It's not the loud ...my Harley Davidson Switchback is a bit louder....but it's great to just get out in the wind and enjoy your time riding...

[@SeanFillner]

Like I keep saying the camera mic does no justice to any exhaust mods. I actually am finding it pointless to record the sounds of the bikes...

[@geraldlooman7130]

Change it to the carbon fiber

[@SeanFillner]

I love the oem look

[@LEVELMotorsports]

Commenting on the ugly stock exhaust but still have that 12 lb horrible looking resonator chamber on there? Get rid of that thing and get an actual quality silencer with a dB killer and not that eBay knock off exhaust and it’ll sound sweet. 👍 You got an insane deal on that header if it’s genuine.

[@SeanFillner]

Bike has been sold.

[@javierc2726]

Little advice Try going to the point The camera moves too much, it is annoying

[@SeanFillner]

Little advice Find another channel to watch.