[pingywon]

Hey gang,

I'm new to all of this. I took my stock exhaust off my 2018 Duke and it sounded amazing. I know there are lots of slip-on exhaust solutions and I have seen the CAT deletes.

Generally speaking.... what are the pros/cons of each or both?

Could I just have someone fab a straight pipe to replace the stock exhaust? Do I wanna keep the cat? do I wanna remove the cat and keep the exhaust? What combo is going to screw with back pressure to the point of losing performance or even worse having issues with the bike running right?

What is ya'lls take on this:

https://www.ebay.com/itm/Delkevic-DE-CAT-KTM-390-Duke-RC390-XOval-13-5-Titanium-Muffler-Exhaust-Slip-On/173757451165?fits=Model:390|Submodeluke|Make:KTM&epid=23028387789&hash=item2874c04b9d:g:k-8AAOSw0xtcSLms:sc:UPSGround!19602!US!-1


TIA

 

[pingywon]

Really? Im surprised no on has any insight to give or add. :*(

 

[Mirius]

I’m sure many could contribute but I’m not sure I fancy attempting a comprehensive reply to such a global range of questions.

 

[Mirius]

Hey gang,



Im new to all of this. I took my stock exhaust off my 2018 Duke and it sounded amazing. I know there are lots of slip on exhaust solutions and I have seen the CAT deletes.



Generally speaking.... what are the pros/cons of each or both?

Ok. Without knowing what you are trying to achieve, this is working in the dark. I’m going to assume it’s mostly sound. If you want to know more about power then register with the RC390 forum and start reading.

Could I just have someone fab a straight pipe to replace the stock exhaust? Yes. It will be loud. Be prepared to buy a good piggyback and be prepared to spend money on tuning

Do I wanna keep the cat? Maybe. Removing it will make it louder

do I wanna remove the cat and keep the exhaust? What combo is going to screw with back pressure to the point of losing performance or even worse having issues with the bike running right? Too many possibilities here. The more you change the more you need to spend getting the bike running right. I’d suggest you can probably safely get away with either a cat delete or a change of slip on without a piggyback but it’s at your own risk

What is ya'lls take on this:

https://www.ebay.com/itm/Delkevic-D...d:g:k-8AAOSw0xtcSLms:sc:UPSGround!19602!US!-1



They make some nice sounding exhausts. Can’t comment on this one.

 

[Hedgepig]

I went with a Tyga header and secondhand Arrows GP Gun rear with Rapid bike EVO exclusive piggyback . No dyno test but seat of the pants says smoother bottom end more shove in mid range would probably pull higher gearing . With db killer out it is very loud even with it in I don't know how it could achieve road legal status ( it is eu stamped ). Back in the 50's my Dad and his mechanic would tune his mxer's a little at a time meticulously recording every small step until an engine failed then rebuild the engine and NOT taking the step that broke the motor his bikes usually out performed the works bikes .

 

[KTMasean]

The question is probably for the second gen Dukes of which I know nothing.
The first gen (from 2012 to 2016) has been played with to exhaustion, exhaust wise and the majority of the aftermarket (quality) exhausts all produced less power than the OEM one.
TYGA's RC set up (full system) gives a proven increase of power (one would expect this from a professional tuner) and I believe the OEM Akro plus Akro flash by KTM also improved the power marginally.
For the first gen, I don't know of any (quality) manufacturer that produced an exhaust making it better.
I have tried the Ixill Hyperflow and MIVV Ghibli and am back riding the OEM set-up (with a PowerTRONIC).
An often overlooked advantage of the first gen Dukes is in case of a drop to your right.

 

[John390]

one of the biggest advantages of removing the cat and "tea kettle" resonator is weight. Those are very heavy in comparison to an s shaped pipe.

My Delkevic system saved in the neighbourhood of 16 lbs over the stock cat, resonator and muffler with piping.

 

[craig johnson (craigj172)]

Hi I have been running the delkevic full system with no issues, after my 2nd service the Tec put another KTM map on my bike for free and made a huge difference to how it ride much smoother at lower rpm I have the system up for sale now as I just swapped my 390 for a Harley fat bob

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[pingywon]

Hi I have been running the delkevic full system with no issues, after my 2nd service the Tec put another KTM map on my bike for free and made a huge difference to how it ride much smoother at lower rpm I have the system up for sale now as I just swapped my 390 for a Harley fat bob

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Is that an older version or something?

The can looks very different than this one:

https://www.ebay.com/itm/Delkevic-D...Titanium-Muffler-Exhaust-Slip-On/173757451165

 

[pingywon]

one of the biggest advantages of removing the cat and "tea kettle" resonator is weight. Those are very heavy in comparison to an s shaped pipe.

My Delkevic system saved in the neighbourhood of 16 lbs over the stock cat, resonator and muffler with piping.

Did you retune after the cat removal?

this listing says that you dont need to and I am curious about that

https://www.ebay.com/itm/Delkevic-D...Titanium-Muffler-Exhaust-Slip-On/173757451165

 

[craig johnson (craigj172)]

Is that an older version or something?



The can looks very different than this one:



https://www.ebay.com/itm/Delkevic-D...Titanium-Muffler-Exhaust-Slip-On/173757451165

Hi, delkevic do many different end cans for the Duke/RC 390 mine is a 3inch carbon and stainless they all use the same cat delete pipe just different end can

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[craig johnson (craigj172)]

Did you retune after the cat removal?



this listing says that you dont need to and I am curious about that



https://www.ebay.com/itm/Delkevic-D...Titanium-Muffler-Exhaust-Slip-On/173757451165

You don't have to retune at all but you can get smoother lower end if you ask KTM mechanic to put the right map on for you they did it free for me but as I said you don't have to

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[pingywon]

You don't have to retune at all but you can get smoother lower end if you ask KTM mechanic to put the right map on for you they did it free for me but as I said you don't have to

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Thanks for the info! I wish your can looked like the one in that listing... I would be interested in it

 

[John390]

if you see my signature, you will see that I have a Rapidbike Evo installed, so yes, its tuned. By me, and also by the auto tune.

Once I did the short intake runner, open airbox, full exhaust and larger injector, I found that I had to tune it more myself than auto tune.

I worked on it a bit at a time, and got it very nicely tuned.

I suspect that with the STOCK airbox you wouldn't need a tune at all, but with even partially opening up the airbox you will need at least some sort of tuning device.

My bike ran a bit lean with just the stock baffle removed and a mostly open airbox. Ran fine really, but you could tell it was lean with a fair amount of popping and it was prone to stall on downshifts to 1st gear.

 

[John390]

that short can must be pretty **** loud! my 14" one is quite loud.

 

[Mirius]

Having blown up a bike engine (not a Duke) by running it just a little bit lean I’m now a bit wary of repeating the (expensive) experience and recommend getting a tune in there for anything more than a slip on change. If you have a gen 1 bike then the stock ECU has more flexibility and I reckon decat is fine but open air box starts to tread the line.

 

[KTMasean]

Most people today would benefit more, health and ride wise by losing some 7.5 kg.
The "tea kettle" weight sits nice and low.
Another weight advantage can be gained by changing to a Li-Ion battery.
After 2 different conventional exhausts setups, I moved back to the tea-kettle.

one of the biggest advantages of removing the cat and "tea kettle" resonator is weight. Those are very heavy in comparison to an s shaped pipe.

My Delkevic system saved in the neighbourhood of 16 lbs over the stock cat, resonator and muffler with piping.

 

[John390]

yep, the weight is low, for sure. no question that the loss of weight from the battery up high would be even more beneficial for handling.

The bike will always benefit from weight reduction, no matter where it is. The brakes and engine are small on this platform. Dropping substantial weight is going to help both.

My bike would power wheelie in 1st, with me leaning over the bars a bit. First time it happened, I was very surprized to be honest. Never did that before.

 

[abduke2017]

hello everyone..want ur input and knowledge on this one.. so i got a mint condition my2016 duke 390

 

[astromars]

hard to tell by the photo but if that is a 'solid' baffle plate in the pipe there isn't much room for gasses to get by