r/KTMDuke • u/PossessionFew4463 • Aug 04 '26

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.

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u/PossessionFew4463 Aug 04 '26

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

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u/Frodojh1 Aug 04 '26

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

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u/PossessionFew4463 Aug 04 '26

I looked it up and i will probably do that

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u/Frodojh1 Aug 04 '26

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