Author Topic: Muffler Removal on 1250 and air/fuel  (Read 8228 times)

Offline Ves

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Muffler Removal on 1250 and air/fuel
« on: October 25, 2009, 11:56:28 PM »
I was watching this video...  http://www.youtube.com/watch?v=t80JTONwbSc

So, one of the options the guys shows is just the Bandit exhaust without the muffler... just the pipe.  It's also interesting that the last option he shows is a full exhaust.  Interesting that the full exhaust with can is actually louder than the standard exhaust with just a pipe (no can).  Then I got to thinking about it.  This makes sense.   A lot of BMW R1150R owners (like I use to be and like I did) just take the muffler off and run a short stubby pipe... and it works really well... nice sound... loose about 14 lbs...  because the catalytic converter is actually doing a lot of the sound deadening and is probably a bigger resistance to flow than the muffler...

So, that got me thinking more... you could probably put just about anything on the stock 1250 header/catalytic converter and it might sound pretty good... So something like this...



All you need is a connector pipe... just a regular piece of stainless exhaust pipe bent to fit...  The obove muffler can be had for about $50 on Ebay...  custom bent pipe... $20?... 

Then I got to thinking about the fuel mapping...  The new Bandit 1250 has a closed circuit system, right?... Says in the manual, "The air/fuel ratio is compensated to the theoretical ratio from density of oxygen and exhaust gases... more fuel is supplied if detected air/fuel ratio is lean... "

so removing the muffler will cause the fuel injection to automatically compensate for any slight leanness that may result from the decrease in back pressure... right? 

Yeah, if you put a pipe on there with no muffler and no catalytic converter you'd probably increase the flow so much, and lean it out, that you'd probably be outside of the range that the control module can adjust for... but that's highly unlikely if you leave the catalytic converter in place...

Am I making sense?... am I missing anything?

Offline Ves

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Re: Muffler Removal on 1250 and air/fuel
« Reply #1 on: November 10, 2009, 11:50:33 PM »
Nothing beats trying it...   :trustme:

Comparison of size... Yeah, that's a little bit smaller...


Hung it just to see how it's gong to look... Love that gray carbon fiber...


View from the back...



So, here's a soundbite of the muffler slipped onto my header, with the baffle removed...

http://www.facebook.com/v/1147258250226

Now all I need is the local muffler shop to make me a pipe to connect them... mmmmmmwahahahahha...
« Last Edit: November 10, 2009, 11:53:14 PM by Ves »

Offline stormi

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Re: Muffler Removal on 1250 and air/fuel
« Reply #2 on: November 13, 2009, 12:06:14 AM »
because the catalytic converter is actually doing a lot of the sound deadening and is probably a bigger resistance to flow than the muffler...

All you need is a connector pipe... just a regular piece of stainless exhaust pipe bent to fit...  The obove muffler can be had for about $50 on Ebay...  custom bent pipe... $20?... 

I'm far from an expert on this, but if you look here:
http://forums.banditalley.net/index.php?topic=8930.0

This is what I did for Dita, in lieu of replacing with stock when her pipe was done.  I supplied the mid pipe, and it cost what,.. $50?  But this is Canada, we get bent over for almost everything.
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Offline Ves

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Re: Muffler Removal on 1250 and air/fuel
« Reply #3 on: November 15, 2009, 01:03:13 PM »

I'm far from an expert on this, but if you look here:
http://forums.banditalley.net/index.php?topic=8930.0

This is what I did for Dita, in lieu of replacing with stock when her pipe was done.  I supplied the mid pipe, and it cost what,.. $50?  But this is Canada, we get bent over for almost everything.

Cool... I'd say that looks pretty good for $50...

Well, I finally got around to finishing mine... here it is in all it's glory... Still need to tighten everything up... I sanded the pipe and painted it with high heat paint... Looks a little industrial, but I don't mind that at all...  I rode it around with the baffle out and it's just a little to loud... not much, because as you get up to speed the wind is actually louder... But I don't want it to be annoying.  With the baffle in it's got just a bit of growl... I'll probably punch some small holes in the back of the baffle and strike a perfect middle ground...  Even with the baffle out it runs really well... actually seems even stronger on the bottom end, if that's possible... smoother also.. if that's possible... doesn't back fire... So I'm guessing the computer is compensating... I'll check the plugs to make sure...  It's so much smaller than the stock exhaust and really opens up the right side... I like it...  Total.. just over $100...







I still have to figure out what I want to do about the center stand... right now it hits on the bottom of the shock so I could just put a piece of plastic in there, as a bumper, and I'm done, or maybe set up a stop somewhere else.