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Discussion Starter · #1 ·
Anyone been wondering what it actually looks like? Well wonder no more! Thanks to one of the lads on the Aussie FB Duke 200/390 page he decided to not let a brand new bike hold him back.
If you look at the pics and the self study guide SM posted http://www.ktmduke390forum.com/foru...ance/1810-ktm-duke-390-self-study-manual.html
you can see that he basically shortened the system instead of running back up and down the pipe before exit. The final pic shows the bottom pipe where he cut the corner and top out so it exits faster. He also pulled the snorkel off the airbox, unsure of the improvements. Its been said that its flowing easliy but im unsure if any HP has been lost or gained as ther has been no dyno work done.







 

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So what is the point of this mod? What is it going to do for the bike?

I am also skeptical that it could have negative consequences for the bike. A decrease in horsepower would suck.
 

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Just look at all those chambers :eek:
 

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So what is the point of this mod? What is it going to do for the bike?
Probably just to make it louder and a bit lighter.

As AOD points out, it's tinkering with the tuned length of the exhaust. And while that may not cause too much of a problem, it certainly won't be doing much good.

That said, removing the mesh walled chamber (presumably the cat), might actually help gas flow a bit. Not so you'd really notice though.

bm
 

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Discussion Starter · #8 ·
It was done for noise and because he could I guess but I would really like to see dyno results so I could understand if there was a gain or loss.
 

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Just joined up and stumbled on these familiar pics. This is my handy work.

I had no concern for power gains or losses as I don't see the point. If I could somehow gain 20% more power from the bike it still won't throw you off the back.
I decided I would prefer to potentially loose to a stock bike by 2 lengths than to see my neighbours check their mail boxes when ever I drive past.

I planned to do the cutting over a few attempts so I could keep a check on dB levels as well as any change in tone. I purposely left the cat intact on the first try. It will go next time I open it up as well as removing the outlet pipe and replacing it with one or two sizes bigger and bell mouthing the inside end.

All up my first cut and shut took about 3hrs and cost two cutting disks, one spray can and some welding wire. The second cut and shut should be quicker as I know I can do it by just cutting the bottom off rather than the whole box in half.

I know I'm not the only one who would be much happier with their dukes if they didn't sound like postie bikes and would prefer a better noise to a potential/unverified power level/delivery change. So when I get around to stage two I will share the results either here or FB
 

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I know I'm not the only one who would be much happier with their dukes if they didn't sound like postie bikes and would prefer a better noise to a potential/unverified power level/delivery change
@MattPorter: Firtly, thank you very much for the photos of the stock and explaining a part of the removal process. I really appreciate it^^

I really like the noise the stock ones make at 6000~9000RPM range (guess it grows on you) but was planning on doing something similar hoping i can hear the "braaaaap" noise more like on a high performance motor, could you post a vid to show us how it sounds now?

Cheers,
Vijai
 
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