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Discussion Starter #1
i put slip on's on my 08 dyna lowrider and it started running really bad. put the stock mufflers back on and ran good again. anyone tell me why. and what to do to fix this problem. just wanted it to be louder.
 

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Just passing thru
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On an 08 your O2 sensors should compensate for the air/fuel mixture change that can occur when changing the air flow thru the engine by modifying your exhaust and or using a high flow air filter.
 

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On an 08 your O2 sensors should compensate for the air/fuel mixture change that can occur when changing the air flow thru the engine by modifying your exhaust and or using a high flow air filter.
I respectfully disagree.

The closed loop function on these bikes is not a true Alpha-N closed loop system, like those on volkswagens for instance.

They use only narrow band o2 sensors and only apply closed loop running while under steady cruising, or at idle.

When you are accellerating, or decellerating, the ECM reverts back to a refrence table programmed in to the ECM to determine how long to open the injectors, and when to deliver the spark.

When ever you change the flow characteristics, adding pipes, or high flow air filter, you need to compensate the fuel to meet the added flow demands of the motor.

There is no way around it. You need a fuel management system. The only ones that work with the closed loop function are the SEPST, or the Master Tuner from the Turbo Shop.
 

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Well I'm going to respectfully disagree with me too. I meant as a package but thought thats the only way they came. Thanks for the info.
 

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What do you mean "running real bad " ? I changed the mufflers on my '07 and it runs fine. :confused:
 

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A buddy of mine put Vance & Hines slip ons on his Ultra Classic and it ran like a turd. Blubbering and backfiring. He took it to the Harley dealer and they remapped the fuel injection. It took about 1 hour to get it back and it ran fine after that. It cost him about $120 bucks though. But that was cheaper than a Vance & Hines Fuel Pack (about $300).
 

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Discussion Starter #8
by running bad i mean that it had a rough idle and wouldnt stay running kept trying to shut off at stop lights was fine if was running it wide open. when i changed to slip ons it ran great for about 2 weeks then this started to happen. i changed them back to the stock ones and it ran fine
 

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:confused:The more I read about slipons the more confused I get. I was thinking of changeing to a louder pipe if I keep the bike, was told by the dealer it would be ok not to worry about doing anything. begining to think I should leave well enough alone. XL1200L
 

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Well I thought this was an interesting read in the new j&p catalogue.

S&S Muffler and a/c quick set up kits are the perfect way to balance the performance budget. Kits include a set of S&S performance mufflers and a high flow air cleaner or single bore tuned induction system that will fit either a stock carb or a stock 2001 up single bore fuel injected throttle body. A jet kit is included in kits for 2006 and earlier models to dial in the stock carb for maximum power gains and improved drivability when installed on carberated bikes. Kits for 2007 and later models do not include a jet kit since all 2007 models are fuel injected. When a quick set up kit is installed on a fuel injected engine that is NOT equiped with a closed loop efi, it is recomended that the a/f ratio be checked by yourlocal dealer to ensure that the engine is receiving sufficent fuel in all rpm ranges. However, we have found that late model closed loop fuel injection systems can EASILY compensate for changes in fuel requirements from the installation of a quick set up kit

I made my own slip-on's

Now the only problem I see is that they are set up lean from the factory. so the puter adjusts back to the 14.7 to a/f ratio even with the added air flow in and out. Imo a tuner is always the best way to adjust to a richer a/f ratio but adding slip-on's and a/c to a closed loop system is not the kiss of death. However 14.7 is a little on the lean side and heat kills so I added a set Xied's, cheap and helped with heat and surge. So It is my opinion that the delphi systems are a little better than most think and can compensate back to stock values within reason ie... a cam swap would cause problems or drag pipes and a highflow

Is it possible after a couple of weeks of riding you developed an exhaust leak from vibration? That may have helped induce an overly lean condition causing the problems you described
 

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Wouldn't the wide-band O2 sensor cables work in this application? Night Rider website has a lot of good gouge on this stuff. Changes the O2 sensor from Narrow-Band to Wide-Band. It will enrichen fuel ratio and perhaps doink your gas mileage a bit, but you should see an increase in throttle response, performance and the bike shouldn't run as hot, especially running the parade route or sitting in traffic.
 
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