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Author Topic: Mufflers and Mixtures?  (Read 508 times)

Arizoni

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Mufflers and Mixtures?
« on: June 09, 2011, 11:17:05 PM »
After reading about the need to re-jet the carburetor when changing the muffler or inlet filter on the older carburetored Enfields I got to wondering, if I change the muffler on my UCE to a less restrictive type will I have to worry about the fuel/air mixture?

My common sense tells me that with an O2 sensor and computer controlled fuel injection the computer should be smart enough to see the lean condition and figure out what is needed to accommodate the change(s).   It should then make the needed adjustment as its needed.

Is my common sense correct or is my common sense more like my wife thinks it is?  ???
Jim
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1999 Miata 10th Anniversary

higgins

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Re: Mufflers and Mixtures?
« Reply #1 on: June 10, 2011, 12:26:09 AM »
I changed mine to the EFI silencer with no problems at all.  Occasional backfire that sounds pretty cool. Runs fine.

JesterNT

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Re: Mufflers and Mixtures?
« Reply #2 on: June 10, 2011, 01:07:13 AM »
Just adding a new muffler the fuel computer will compensate.  If you add a K&N air filter or the like you might move too much air for the fuel MAP to adjust.  
Quando Omni Flunkus Moritati

Maturin

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Re: Mufflers and Mixtures?
« Reply #3 on: June 10, 2011, 01:11:34 PM »
Hey brother! Your lovely wife has no idea. Her smart husband just bought a plug-and-play toy! It adjust itself - fortunately a rider is still necessary  ;D
Best regards
Maturin
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Okie Enfield

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Re: Mufflers and Mixtures?
« Reply #4 on: June 10, 2011, 01:48:09 PM »
Gonna have the EFI silencer on later today  ;D If I have any issues I will be sure to post but everything I have read says its plug and play.

GreenMachine

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Re: Mufflers and Mixtures?
« Reply #5 on: June 10, 2011, 02:16:12 PM »
thats the beauty of those new machines..goood luck.
Oh Magoo you done it again

barenekd

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Re: Mufflers and Mixtures?
« Reply #6 on: June 10, 2011, 03:01:17 PM »
On a dyno run, my bike, equipped with the English EFI muffler and a K&N filter, was in the groove mixturewise. It went a bit rich above 5500 and quit by the ignition cutoff  at 5900.
Close enough  for gummint work, I'd say.
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Sub

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Re: Mufflers and Mixtures?
« Reply #7 on: June 11, 2011, 01:31:25 AM »
I changed mine to the EFI silencer with no problems at all.  Occasional backfire that sounds pretty cool. Runs fine.

Thats good to hear barenekd. I just made my own custom air box (kind of like ACE, I'll post something about it later). I also have the EFI. It ran great today on my 200 mile ride. the only difference I noticed was that it was a tiny bit rougher at stop lights. I need to increase my idle just 100 rpm or so and I think that will take care of it. I didnt notice a difference power-wise with the new intake, but it sure does sound cool, and I get all that storage back with the OEM air box is. The intake noise on the UCE motor is actually really nice - sort of a deep, howling growl.

I need to pull my plug after that long trip and see what my plug looks like - I guess thats the only way to tell if I'm running too rich/lean without special tools..

Ducati Scotty

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Re: Mufflers and Mixtures?
« Reply #8 on: June 11, 2011, 05:45:38 AM »
Sub, keep an eye on your MPG too.  Even though the plug looked fine I dropped 10% when I tried the cone filter right on the throttle body.  I suspect there wasn't enough plenum to smooth out the air flow and the MAP sensor was being affected.

Scott

Sub

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Re: Mufflers and Mixtures?
« Reply #9 on: June 11, 2011, 05:55:09 AM »
Wow, if there is one thing I dont have a concern about on this bike its mpg! :) I'm afraid to say I dont even watch it.

If your mpg was worse, thats a good sign though - running richer as opposed to leaner, which is my main worry.. I dont want to hurt my engine!