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Discussion Starter · #1 ·
Has anyone tried to just replace the head pipe? I am curious to know if removing the catalytic converter but leaving the factory muffler will free up any HP while still keeping it quiet.
 
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Discussion Starter · #3 ·
I thought about buying one until I decide exactly which low pipe I want

Im sure it'll give it a little more growl ditching the cat but hard to say how much.. Maybe one of the people with the full yoshi systems can stick the stock muffler on real quick for the sake of knowledge :)
Yeah, if it will fit. Hey Shoebacca78 are you listening? I'd love a video and DB meter readings on this.
 

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I was thinking about doing this....stock look with a little more sound. It'd be nice if it actually produced a little more power

2004 Honda 919
1978 Triumph Tiger
1989 Honda GL15 ( A work in progress...)
2014 Honda Grom ( Soon to come)
 

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Yeah, if it will fit. Hey Shoebacca78 are you listening? I'd love a video and DB meter readings on this.
If the muffler works with the stock pipe, it should be the same the other way

Also! One of you guys with the stock pipe, cut that sucker in half and cut the ends off in the name of science!

Maybe even drill the rivots off the cap and see how it looks?
 

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Its gotta be worth the endeavor considering the yosh slip on yields the same HP as the stock muff.

I'll cut my can open in the name of science.
For a cat delete a section of ~7/8" o.d., probably 0.02thin, is required.
 

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Discussion Starter · #8 ·
Thankyou

Sent from my DROIDX using HondaGrom.net mobile app
 
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hopefully i get my exhaust tomorrow. then i can hack it up. i actually wanted to just shorten the stock can. but i don't have a welder, so i would have to down my bike for a lil while. an that wasn't gonna happen.
 

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I thought this thread would catch on better. Anyone try this yet?
 

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Most modern cats will only restrict 5% or so power. You loose more through the drivetrain than anything.

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Hello from England, I have cut the end of the cat bulb --removed the cat and welded it back together so that it looks original. Result is free reving with a little increase in noise from the exhaust but not enough to make you stand out with neighbours or police. I still have the Honda "E1" markings so unless somebody really knows about the bike they would not be able to tell the difference.
No great increase in performance,perhaps 2mph giving me to speed of 70mph.
 

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Hello from England, I have cut the end of the cat bulb --removed the cat and welded it back together so that it looks original. Result is free reving with a little increase in noise from the exhaust but not enough to make you stand out with neighbours or police. I still have the Honda "E1" markings so unless somebody really knows about the bike they would not be able to tell the difference.
No great increase in performance,perhaps 2mph giving me to speed of 70mph.Stock silencer and done after the 600 mile service so as to retain warranty.
 

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I have installed the MSX Sport head pipe and run the stock can. Noise wise I notice no difference compared to stock. Power wise hard to say. When I ride with my other grom buddies that have exhausts they dont pull away from me. Some think mine has better bottom end power. The way I see it is with a reset ECU I get a few more MPH until it remaps itself and thats with a stock exhaust. So the big restriction isnt the exhaust its the ECU. But the head pipe doesnt hurt, I think it gets up to speed faster, top speed is maybe a little better. Again ecu gets in the way. I wish I could get a better looking quiet exhaust but I havent found one. I like the idea of the CBR125 exhaust on the grom, low mount and quiet.
 
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