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For whatever its worth, and I've not seen dyno charts to prove or disprove yet, but these smaller motors typically like some back pressure.

Running a wide open exhaust, or close to it may actually result in some loss of power as compared to stock.. Just something to consider. :2cents:
Yes I can vouch for that. I lost mid range power on both CBR250 & 300 by adding a freer flowing slip on with less back pressure.
You didn't need a dyno to work it out, it was that noticeable. If it did add any top end power then that wasn't noticeable. The CBR's are a single though and don't rev so high, 10,500 RPM redline from memory.
Possibly more to be gained in top end power on the N400.
 
Yes I can vouch for that. I lost mid range power on both CBR250 & 300 by adding a freer flowing slip on with less back pressure.
You didn't need a dyno to work it out, it was that noticeable. If it did add any top end power then that wasn't noticeable. The CBR's are a single though and don't rev so high, 10,500 RPM redline from memory.
Possibly more to be gained in top end power on the N400.
I'd read stuff like this other places, so I was confused when the post above said there were no performance declines noticed. I guess I'll have to save my pennies for a nicer full system and dyno tune.
 
Just to add to this. Backpressure is not why you lost power. It’s the lack of scavenging from too big or short of a pipe.

Think of it as a straw vs water hose. If you blow the same volume through each, the straw will have higher velocity and pressure than the hose. However the hose might have zero pressure because it’s too big and low flow for the given volume. Now add in exhaust pulses. If you have too big of a pipe you loose velocity (momentum) going through the tube and it doesn’t flow well.

There’s a size limit when it comes to exhaust. You want a diameter that doesn’t restrict flow, but also that the momentum of the exhaust is still moving fast enough to create a negative pressure behind it to pull the next pulse through the tube. Make sense? Also rpm has to be taken into consideration. That’s why people notice the loss of low rpm and a slight gain at high rpm. Aftermarket pipes might be too big for low rpm but they might be just right for the higher rpm. It’s because the factory pipe is a compromise of low rpm effeciency and high rpm restriction.
 
Just to add to this. Backpressure is not why you lost power. It’s the lack of scavenging from too big or short of a pipe.

Think of it as a straw vs water hose. If you blow the same volume through each, the straw will have higher velocity and pressure than the hose. However the hose might have zero pressure because it’s too big and low flow for the given volume. Now add in exhaust pulses. If you have too big of a pipe you loose velocity (momentum) going through the tube and it doesn’t flow well.

There’s a size limit when it comes to exhaust. You want a diameter that doesn’t restrict flow, but also that the momentum of the exhaust is still moving fast enough to create a negative pressure behind it to pull the next pulse through the tube. Make sense? Also rpm has to be taken into consideration. That’s why people notice the loss of low rpm and a slight gain at high rpm. Aftermarket pipes might be too big for low rpm but they might be just right for the higher rpm. It’s because the factory pipe is a compromise of low rpm effeciency and high rpm restriction.
Good info. I would like to add that I never got either of my bikes tunes to suit the pipes and on relfection it was probably more low to mid range loss rather than all of the mid range.
I wasn't bothered overly though as I was changing the pipes more for weight, looks and sound reasons in that order. Not performance.
 
Oh my..they have one with a GREEN Tip... Stainless Steel ceramic coated black Shorty Exhaust, Kawi color Aluminum Tip... that is not to shabby if ya got 230.00 laying around..


Found this sound clip video in red tip..



I really like that Green tip with the bike...
 

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Oh My Gawd... My lil bike has grown up.. 20 minute install and now I wait a week while it rains(again), to hear it in action... sigh.. but here is a small sound clip right after easy peasy install.. I am pleased! Amazon: https://amzn.to/2OR84BB





EDIT: Weatherman lied and roads are dry.. First Ride around the block with the new Coffman's Slipon muffler.. Sounds lovely....

 
Matching cuff! Hows the dB level? Ear plugs required you think.
I knew I forgot to add something ..It is much quieter than your average HD.. Don't know how well this app works.. But with the Insert in.. I used a DB METER app on android phone.. it rated it 64db average and 84db max (loud music). To "me"..it looked like it was around 80-81db on the max cranks sitting still under a carport.. Which means the app seems low..lol But after looking it up online with others experience.. this seems about right with insert.

Personally, I am already one of those people who always says "Huh?" when asked a question and I also have the ringing in the ears for years now... I barely heard the stock system. so I am a bad judge in this respect.. I didn't use to mind loud sounding bikes, I more or less liked it.. and it will be awhile before I can judge it first hand at any length of time... hope that helped..

:grin::nerd::grin:


Compared to this chart... 85db should be safe for 8hours.. jus'sayin huh? speak up!
https://www.noisehelp.com/noise-dose.html
 
Can anyone speak to how loud this one is? Basically is it make-your-neighbors-hate-you loud or just loud?

it's just louder with insert in... it is much quieter than your average Harley if that helps...
to "me"..in looks and sound it is worth every penny.. DB meter 80-84 .. Harleys with after market are usually around 95+ DB..
 
it's just louder with insert in... it is much quieter than your average Harley if that helps...
to "me"..in looks and sound it is worth every penny.. DB meter 80-84 .. Harleys with after market are usually around 95+ DB..

Thanks, I am probably leaning more towards a scorpion or m4 exhaust now but still good to know I have options.
 
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