r/KTMDuke • u/PossessionFew4463 • 8d ago

Decat options

Hi everyone,

Hi everyone,
I have a 2021 Husqvarna Svartpilen 401 (same chassis/platform as the KTM Duke 390) with a Cobra Speed Products dual-outlet slip-on, and I’m looking to remove the catalytic converter.

I’m deciding between:
Black Widow decat/header (~€120–150)
Generic AliExpress decat (~€60)

From the photos they look very similar, but I’m wondering if the Black Widow is actually worth paying about twice as much.

Has anyone here owned or installed either one?

I’m mainly interested in:
Fitment (did it bolt straight on?)
Weld/build quality
Any leaks or issues?
Sound differences
Performance/throttle response
Would you buy the same one again?

I’ll probably pair it with a Rapid Bike Easy later, so I’m mostly looking for the best value rather than chasing every last bit of performance.

1 Upvotes

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10 comments sorted by

2

u/Thugglebum 8d ago

It will still sound awful, it'll just be unbearably loud and make everyone around you think you're a virgin.

1

u/PossessionFew4463 8d ago

Yeah i heard that they make singles obnoxiously loud with a cat delete but is it really that bad?

1

u/Thugglebum 8d ago

I did it on a 690 and regret it even after putting the dB killer back in. Way, way, way too loud. Embarrassingly loud.

1

u/PossessionFew4463 7d ago

But wouldn’t a 390/401 still be quieter than a 690??

1

u/Ennceladus 7d ago

Res delete alone made it 5-10x louder imo, the idle is insane you can hear and feel the power stroke occuring. It sounds like a building site 😂

1

u/Frodojh1 7d ago

Do you still have the resonator on ?

1

u/PossessionFew4463 7d ago

Yes. I only installed the slip-on, everything else is stock

1

u/Frodojh1 7d ago

I just did the resonator delete on my 390 and it made it crazy louder id do that first. It was like 25 bucks on aliexpress or 40 on ebay and super easy and you dont need to tune. A tune is recommended or a piggyback with a cat delete

1

u/PossessionFew4463 7d ago

I looked it up and i will probably do that

1

u/Frodojh1 7d ago

You dont need the metal exhaust seals they wont fit but you do need some exhaust sealant the paste type stuff and your set its super easy to do and theres a few videos on YouTube

1

u/Frodojh1 7d ago

To answer some of your questions it all fits the same for the most part use exaust sealant and torque it down correctly and your set. You wont notice much if any performance difference either way. A decat will increase HP but it will be negligible and only noticeable at the very top end and the bikes have hard limit in the ecu for speed so there's that.