duke 390 modified stock muffler ? - KTM Duke 390 Forum
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post #1 of 46 Old 02-07-2015, 02:15 AM Thread Starter
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Question duke 390 modified stock muffler ?

has anyone tried this on the duke 390 ?
what are the possible downsides ?
will it harm the engine ?
will it affect the acceleration / top speed ?

https://www.youtube.com/watch?v=TAk1ABgcO04&app=desktop
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post #2 of 46 Old 02-07-2015, 03:52 AM
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I've been watching a stock exhaust on eBay for the purpose of modification. Any modification to it will change the power delivery and require fuelling changes. Without fuelling changes you risk blowing the engine.
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post #3 of 46 Old 02-07-2015, 04:07 AM
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I have to add that I wouldn't do what they did though, that's just heresy, might as well run a straight through.
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post #4 of 46 Old 04-19-2015, 05:43 AM Thread Starter
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can u suggest me a cheap / safe / good exhaust system?
i'm very much happy with the duke 390 except the exhaust note!
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post #5 of 46 Old 04-19-2015, 06:58 PM
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Quote:
Originally Posted by Sinha View Post
can u suggest me a cheap / safe / good exhaust system?
i'm very much happy with the duke 390 except the exhaust note!
There are lots out there that'll make it sound better. If I were you, I'd look at getting a PowerTronic and air filter first though.

Honda CBR400RR --> Suzuki Raider 150R --> Suzuki DR200SE --> KTM D390 with sauce
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post #6 of 46 Old 04-20-2015, 02:34 AM
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Quote:
Originally Posted by Sinha View Post
can u suggest me a cheap / safe / good exhaust system?
i'm very much happy with the duke 390 except the exhaust note!
Quote:
Originally Posted by malJohann View Post
There are lots out there that'll make it sound better. If I were you, I'd look at getting a PowerTronic and air filter first though.
Not so many that'll make it faster though. I'm keeping my quiet stock exhaust fitted to my bike and my money in my pocket and just laughing at anyone that thinks my bike will be slow because it's quiet.
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post #7 of 46 Old 04-20-2015, 04:50 AM
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I totally agree with all the comments above, Noise does not always = power & as mentioned changing the exhaust may not give you more power, More than likely with more flow you main gain power higher in the RPM range but you might actually lose needed torque & power down lower in the revs, This is the tricky part that needs to be worked out by a good exhaust manufacturer

1 of the main advantages though even if you dont gain any power is the weight loss, The stock catalytic converter is rather heavy so dropping the weight helps your power to weight ratio overall which not only helps acceleration but also braking & handling, Probably barely noticeable to most unless you are racing & going for those extra seconds per lap etc

I am waiting to get my hands on the new Austinracing Hi Slung GP1 exhaust as soon as it is available>

https://www.facebook.com/pages/Austi...54737234631379
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post #8 of 46 Old 04-20-2015, 03:17 PM
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don't forget the famous tunable Supertrapp

SuperTrapp: Performance Exhaust


These really work as advertised. I've had one on my Mini Cooper S for along time and will install one on my next motorcycle (last bike was a 2 stroke.)
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post #9 of 46 Old 05-19-2015, 08:52 AM Thread Starter
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i'm happy with the speed, not looking for any kind of performance boost..
only looking for a better exhaust tone...
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post #10 of 46 Old 05-19-2015, 11:07 AM
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The creators of the 390 Duke, KTM, designed a compact, mass-centralized exhaust system that was carefully synchronized with the ECU's fuel mapping. As MalJohann notes, any change to the exhaust will perturb the air/fuel ratio programmed into the ECU: and this could lead to an excessively lean condition which could seriously damage your motor. KTM has approved the Akropovic exhaust as an aftermarket upgrade. But to use this exhaust also requires the ECU remapping reflash KTM offers.

I think your best bet is to leave the well-designed stock exhaust alone and not worry that it has a civilized exhaust note, as Mechanical_Vandal advises. A 390 Duke is never going to rumble like a Harley!

The Duke exhaust is one of my favorite features of the bike. It is centralized, compact, unobtrusive and effective. It does not require hanging a conventional-style can off the side of the bike - in addition to requiring a remap, this arrangement interferes with saddlebags, precludes (or burns) a pillion, creates extra aerodynamic drag to slow you, and is waiting to be mangled if there is a crash. The "cheap/safe/good" exhaust you are seeking is the one you already have!
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Cheers, Will

"If you don't know where you're going, you might wind up somewhere else."
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