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HD 2007/2008 Engines

High Heat on 2007/08 HD engines

HD 2007/08 Performance Recommendations

Cool your exhaust temperature with the Wide Band O2 upgrade for 2007/08 HD

Harley Camshaft Specification Tables

HD Twin Cam Engine Builds
TC 128 HP 95 CID
TC 100HP Street Engine

The basics of Fuel Injection explained

Rammer Performance Air Cleaners
TC Performance Heads 100+HP

Pro Tuning on a Shade Tree Budget


LC1 Wide Band O2 Sensor Upgrade for 2007/2008 HD Engines

What are the issues with the 2007 HD engine?

Right after the 2007 HD motorcycles were introduced the issue of high engine heat and poor throttle response showed up. Nightrider with its background and experience in fuel injection systems was able to quickly identify the HD supplied narrow band O2 sensors and the OEM EFI operating in closed loop mode as a significant source of the complaints. Even Harley-Davidson recognized that there was an issue and put out an EFI download to improve the situation for FLH's. But this HD supplied upgrade did little to address the real cause of the issue. Harley-Davidson was unable to do much more than it did for the FLH's because of Government EPA regulations and most Dealers had little idea what the real problem was or how to correct it. The most common fix "sold" to riders was a Stage 1 download, SE Race Tuner or installing a PowerCommander or similar "black box" upgrades. None of these upgrades was overly successful at reducing temperature because they never addressed the real cause of the situation which is the ECU operating in closed loop mode. Eventually some of the "black box" aftermarket companies started supplying O2 Eliminators for the 2007 bikes. The O2 eliminators would reduce the heat, but most riders saw large drops in fuel mileage. When the O2 sensor is disconnected from the EFI, the engine is forced to run at an overly rich 12:1 fuel ratio in many circumstances. This is an overly  rich fuel mixture that drops gas mileage and can result in excessive carbon buildup in the engine.

Can the situation be fixed?

What was needed is a Wide Band O2 sensor upgrade for the 07 HD's that would allow the rider or mechanic to set an appropriate AFR for the engine and the way it is ridden. Under most circumstances, the more appropriate AFR is in the 13.5-13.0:1 range. This AFR helps keep engines cooler, provides good throttle response and does not severely impact gas mileage.

Without getting into the heavy technical details, replacing narrow band O2 sensors with a wide band O2 sensor is a lot more complex than just taking the NBO2 out of the exhaust and installing the WBO2 sensor. Narrow band O2 sensor basically only understand a single AFR, 14.7:1. This is a good AFR for gas mileage and water cooled engines. But 14.7:1 AFR produces the highest exhaust temperatures, which is not good for air cooled engines or motorcycles. A Wide Band sensor is able to accurately report on air fuel ratios from 10:1 to 20:1. This makes them ideal for performance and pollution controlled engines. But wide band sensors require special electronic circuitry to process the signals from the sensor and they also produce different voltages than the NBO2 sensor. A narrow band O2 sensor puts out a signal of 0-1 Volts where the wide band sensor electronics puts out a signal of 0-5 Volts, making it seem incompatible with the Delphi ECU.

But this incompatibility between WBO2 and NBO2 sensors can be overcome with some additional electronics.  Nightrider identified and successfully tested ways to upgrade from the OEM HD NBO2 sensor to a wide band O2 sensor. Along the way, some the operating characteristics of the HD engines EFI system were captured by data logging instrumentation. These EFI operating characteristics explained many of the issues that riders see on their motorcycles. It was also established that the WBO2 sensor upgrade would be compatible with all HD Stage 1/2 downloads, HD supplied engine upgrades (103, 110CID), SE Race Tuner, and aftermarket tuning aids like PowerCommander, Fuel Pak, TFI and other devices without requiring the use of an O2 eliminator.

What is the fix for high heat on the 2007 HD engines?

Installing the LC1 Wide Band O2 sensor upgrade and setting it for a 13.5:1 or 13.0:1 air fuel ratio dramatically lowers engine heat and will reduce the instances that the engine goes into high heat/parade duty mode. Because we have seen stock 96CID engines go into high heat mode in 10 minutes of idling in the shade. This means that the OEM HD engines are "on the edge" when it comes to their ability to keep cool. We believe this marginal cooling ability is very critical for HD 110 CVO engines and HD 110CID engine upgrades due to known issues with scored/scuffed cylinder walls occurring. There is also a high probability that this situation is also occurring on the HD Stage 2 103 Big Bore upgrades.

Advantages to the LC1 upgrade Disadvantages to the upgrade
Heat Reduction
Dramatically reduces the exhaust and engine heat by 15-20%. Will reduce the EFI going into high heat mode.

Adjustable AFR
The Closed Loop fuel mixture is fully programmable to any desired AFR.

Works with all HD downloads and engine upgrades. Works with SE Race Tuner. Works with aftermarket tuning aids and does not require the use of O2 eliminators.

Robust Electronics
The LC1 WBO2 electronics have been extensively tested in the automotive world and are very weather resistant.

It Works
The LC1 lowers temperatures and improves throttle response as expected.

Accurately Monitor AFR
The LC1 will allow you to accurately monitor the AFR at any time. Because the fuel ratio is sensed close to the cylinder, it is more accurate than a "sniffer" used on a dyno.

The only sure fire way to ensure the fix works properly is to use two LC1's.

While the size of the LC1 is not large, mounting it on the front of many bikes is not going to be esthetically pleasing. FLH's have hidden space room below the tank, but Dyna's and Softail's do not have that option.
Until we have a WBO2 extension cable available, the LC1 must be physically mounted within 18-24" of the WBO2 sensor.

Performance Upgrades
The LC1 is primarily intended as an upgrade for stock and HD/SE Stage 1/2 upgrades. This is not a replacement for fuel mapping on extensively modified engines, although it is compatible with any engine upgrade.

Don't the HD downloads fix the high heat issue?

The various HD downloads and Stage upgrades do not address the high engine temperature issue. Harley-Davidson is limited by Federal Emissions Standards, therefore can not provide an upgrade that might violate or alter the emissions of the engine. This prevents them from providing a "Fix" that is going to make all riders happy. The Dealers are in the same situation because they risk very high fines from the EPA or State emissions control agencies when they install unapproved upgrades on motorcycles. California is a good example of a State that is beginning to crack down on upgrades that do not meet emissions standards.

What are my options if I don't want to use an LC1?

The use of O2 eliminators has become fairly common on the 2007 engines. When using an O2 eliminators supplied by PowerCommander, TFI, etc., the engine is forced to operate in open loop ECM operation and use the internal fuel map. For a closed loop engine, the fuel map is 14.6 AFR, but the ECM will alter the fuel mixture based on changes indicated in the AFV (adaptive fuel value). These 'fuel trim' values or learned adjustments can richen the fuel mixture several percentage points. The short and long term trim values in the Delphi ECM are the reason that you can actually run upgraded exhaust/air cleaner on the 07>later bikes. Take a look at the DIY voltage dividers.

In the future Nightrider plans on providing a way that you can make your own O2 eliminator for your bike. This Do-It-Yourself O2 eliminator will cost under $10 to make. For those of you that are adventurous, the O2 eliminator is nothing more than a 1Meg ohm resistor replacing the NBO2 sensor. All you need to do is remove the O2 sensor and connect the resistor between the Blue and Gray wires that run to the OEM sensor.

SE Race Tuner gives you full control over the Delphi ECU. Using SERT, you can eliminate the closed loop operation mode, or alter the RPM ranges that it effects the engine. With SERT you can actually richen the close loop air/fuel ratio up to about 14.2:1 by altering the O2 bias table voltages to 750.

There are at least two popular aftermarket ECU's available on the market that can replace the Delphi ECU. The Daytona Twin Tec and Thunder Max ECU upgrades will work without any O2 sensors, or they have an option to add wide band O2 sensors to the upgrade. The addition of the WBO2 sensors with these kits provides a level of "self tuning" for the air/fuel ratio that is accurate enough for accurate tuning on most engines.

Another possible upgrade is the Do-It-Yourself voltage divider. For under $15, you can create a basic voltage dividing circuit that can be used on the OEM narrow band O2 sensor that will raise the closed loop AFR from 14.7:1 to a slightly richer 14.2:1. While this is not as desirable a fuel ratio as the LC1 can deliver, any improvement is going to help lower the engine operating temperature. Click here for the Nightrider DIY article on this upgrade.

Are there any issues with the LC1?

There are no "problems" with the LC1 that Nightrider has been able to establish. The ability of the LC1 to accurately alter the close loop air fuel ratio of the Harley-Davidson Delphi ECU to any desired AFR is well established and works exactly as anticipated.

There are still some questions on how the HD ECU prioritizes the O2 sensor signals. We know that you can not use a single LC1 to control both cylinder and get satisfactory results. If you decide to try a single LC1, install it on the rear cylinder to reduce the heat your feel while riding. While we believe a single LC1 will work on the a single cylinder, we recommend installing two LC1's on your bike. One LC2 WBO2 upgrade for each cylinder, replacing the OEM O2 sensors.

How do I purchase the LC1 for my engine?

The LC1 WBO2 upgrade will be available for sale in early 2009.

Before you order and install the LC1 on your bike, we strongly recommend you review the Innovate LC1 manual and Nightrider LC1 Installation Guide.

How do I install the LC1 on my bike?

Nightrider will put installation information online. In order to access the installation guide, you will be required to get an "access code" from us. We will send you the URL for the online guide and the code to get onto the site. This is to ensure that we are aware of riders that put the upgrade on their bikes. It will also give you access to some very specific setup information for the LC1 that is required to properly configure the WBO2 for your Harley-Davidson.

Is installing the LC1 hard to do?

The wiring of the LC1 to make it work is not very difficult, but finding locations to install a controller for both the front and rear WBO2 sensors can be difficult. While we believe that the engine will run fine with a single LC1 installed for the rear cylinder, we recommend the use of two LC1's. One for the front cylinder and one for the rear.

LC1 WBO2 Upgrade Installation Instructions

The LC1 Wide Band O2 upgrade installation instructions are located on our Training Site at . You will be required to register to get a login on this site. The registration process also requires you confirm your information online through a valid e-mail address.

You may also be asked for an enrollment key. The current enrollment key for this installation instructions is "nightriderfix".

The installation instructions will be periodically updated and improved as better information becomes available.

For other LC1 Installation Information

Information contained on the LC1 Installation Guide site is Copyrighted information and may not be reprinted or distributed under any circumstances. Any person registered on the site caught distributing this information will have their access rights removed.

Recommended Performance Upgrades for 2007 HD Twin Cam engine


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Modification, Installation, Maintenance and Tuning Index  will help you find most of the information you want on one page.

How to get Professional Tuning Results at home
Testing the Innovate Motorsport LM-1 portable air fuel meter

Profession Tuning on a Shade Tree Budget

Veypor VR2 Data Logger and Instrument Panel
Video Installation and Demo
Purchase VR2

Engine Performance
How to Build a
TC96 2007 Engines
TC88 70HP Stage1  
TC95 128HP Stage 3
TC95 100HP Street
TC96 2007 Stage 1/2
EVO 64 HP Stage 1
EVO 74 HP Stage 2
EVO 82 HP Stage 3
EVO 95 HP Stage 3
883 to 1200 Upgrade
Shovelhead Modifications

New EFI for EVO and TC

Performance Gallery
Horsepower Gallery
Evolution 80
Twin Cam 88/95
Evolution Unlimited
Sportster Unlimited
Drag Strip Gallery
Land Speed Racing Gallery
CV Carburetor
Modifying the CV carb
Tuning a CV carb
Selecting a cam
Install a TC 88/95 cam
Install a Big Twin cam
Install Sportster cams

Camshaft Specifications
Twin Cam

Exhaust Systems
EVO Exhaust Testing
TC Exhaust Testing
Khrome Werks AR100 test
Making Drag Pipes Work

Shop Manual
Carburetor Troubleshooting
Finding Manifold Leaks
Cylinder Heads
Pistons and Cylinders
Belt Drive
Shop Manual Appendix
$20 Bike Lift
Plug Wires
Spark Plugs
Engine Tuning
Nitrous Oxide
Motor Oil
Stutter Box
General Information
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Buy Books and Manuals
Performance Calculations
Estimate Horsepower
Estimate 1/4 Mile Time
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Engine Displacement
Exhaust Length
Gear Ratios
Air Density

The Nightrider Diaries
The ramblings of a genius a, a madman and something in between.

Where is Sifton Cams?

Autocom Active-7 tested

Harley-Davidson EFI
-EFI basics explained
-EFI modifications explained

183 HP, 2 carbs, 2680cc

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