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

Trying to get there! Thanks for the comment!

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

Did you notice any power gains?

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

Nice 👍

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

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

Not much if I were to guess.

Initial...

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.

@@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 :)

All 5 bikes 0 issues.

@@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?

@@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!

I ordered 4 at once. Took 5 days IIRC.

You're funny!

@@SeanFillner Really? Nothing?

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

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

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

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.

@@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.

@@El_Rudo thanks for sharing that information.

@@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.

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

When I post a link they sell out fast.

@@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?

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

Did you watch the video? Apparently not.

@@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

@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.

@@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).

@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!

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...

Bike has been sold.

I love the oem look

Little advice Find another channel to watch.