Professional Tuning on a Shade Tree Budget

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Chassis dynamometers have been readily available for several years in the performance motorcycling world. The use of a inertial dynamometer has been the “gold” standard for tuning a performance motorcycle since the early-90s. While few of the early chassis dyno’s had the ability to monitor air fuel ratios (AFR), it really wasn’t required to do a good performance tune on a carburetor bike. Just keep changing main jets until the engine produced the most horsepower. Take the bike out for a quick test ride and make a minor adjustment or two too the jetting, then the rider goes home happy with a well tuned bike.

The emergence of fuel injected motorcycles in the late 90’s required a different standard of tuning than a carburetor. It was easy to set the wide open throttle fuel map on the chassis dyno using similar techniques to doing a carburetor, but the partial throttle fuel maps were a different story. A dyno operator could spend a lot of time accelerating the engine through various RPM ranges and trying to watch the tachometer and listen for engine misses, then make changes to the fuel map. But this method is very hit and miss for setting a fuel injection systems that run based on very exacting fuel maps.

The latest technology in dynamometer’s has added an air fuel monitor and placed a load cell on the roller to simulate road conditions. All of this can be purchased for just under $30,000. Now you are ready to tune EFI motorcycles. Or at least you might understand why your dyno guy is charging $60-$100 an hour for tuning time. They have a lot of very expensive equipment to pay for.

You would think there is an easier and less expensive way to properly tune fuel injected engines after you have made the performance upgrades that you want to your bike. Something that a small independent shop owner, serious racer or home tuner could use to help them tune their fuel injected or carburetor bikes.

Here at Nightrider.com we believe that there is a better and less expensive way for those people who don't have a lot of money to invest in expensive equipment. Over the past couple of years, there has been significant advances in automotive electronics that has resulted in smaller size, lower cost and expanding capabilities for monitoring engine functions. Like it or not, a lot of this technology probably owes its existence to government mandated pollution control laws. These laws forced the automotive companies to invest research and development dollars into sophisticated components to monitor and control engines. The same devices that make sure an engine does not pollute the air can also help tune an engine for maximum power. One of the most useful devices developed is the Oxygen Sensor.

The only problem with Oxygen sensor for performance tuning is the fact that they come in two basic varieties. The simpler narrow band O2 sensor is really only accurate in the 14.2 to 15.2 air fuel range. This is fine for pollution controlled vehicles, but basically useless for performance work. Despite this, many performance enthusiasts have tried to tune with one of the multitude of  inexpensive AFR gauges available for under $150. Few of them realized that the information it gave them was almost useless and they could have done just as much tuning work with a $30 narrow band O2 sensor with an equally inexpensive Radio Shack voltmeter. The more accurate wide band O2 sensors is required for tuning a performance engine. For many years, the O2 sensor alone might cost you $150 or more. And the sensor required several hundred dollars more in support electronics to be able to determine what the AFR really was. These were very accurate, but very expensive.

All of that has now changed. Innovate Technology’s LM-1 portable wide band oxygen sensor gauge has been on the market for a couple of years now. Its small size, accuracy, simplicity and low price have made it a popular tool with the automobile performance crowd since its introduction. It has the ability to data log engine and vehicle operating parameters such as air fuel ratio, engine RPMs, throttle position sensor, vehicle MPH, EGT, CHT, acceleration in G's, and virtually any sensor you could possible have on your vehicle. Its logging ability, display capability and extensive list of add-ons make the LM-1 a very capable tool for performance monitoring, and tuning on the street or the track. The LM-1 includes Logworks software that has the ability to display AFR (air fuel ratio) charts that can be used to update your EFI fuel maps and create very accurate tuning. Surprisingly, this very useful little performance tool has not caught on with the two-wheeled crowd to the same extent as it has with four-wheelers. Nightrider.com tested the basic capabilities of Innovate Motorsports LM-1 in May, 2007 and found it a very capable, precision instrument for any tuning requirements you may have.

Nightrider now offers the LM-1 for sale though its Performance Products web site. We can offer you your own LM-1

How Does tuning with AFR's help me?

 Glad you asked that question. In order to minimize gas emissions, produce maximum horsepower, get good gas mileage or simply have good throttle response requires some very specific air fuel ratio ranges. 

It is also very useful to understand how air fuel ratios vary from very lean to very rich. So here is basic chart of air fuel ratios. The higher the number, the leaner the fuel mixture is. The lower numbers are the richest numbers. Very lean numbers produce high heat and poor throttle response. Very rich numbers produce poor gas mileage and result in carbon buildup in an engine. This is why any vehicle require a wide variety of fuel ratios. There is not a single fuel ratio that handles all operating conditions for your average motor vehicle. The AFR chart listed below is just another view of the AFR recommendations listed above.

But knowing where in your engines RPM and load range can help you tune your engine very accurate for power and gas mileage without putting your vehicle on a dynamometer. No more very expensive dyno time every time you change engine components. All you need to understand is how to apply the tables listed above to your particular vehicle. Building a high power performance engine, then you are going to be on the rich side. But you can also tune your engine so when it is cruising around town it will get good mileage. It is all in applying the required AFR's to your application. Prudent tuning can actually give you the horsepower you want and good gas mileage.

Typical H-D SERT MAP for 2006 and Earlier Bike

Typical H-D SERT MAP for 2007 and Later closed loop ECM Bike

If you are not completely confused by now, you are probably ready to do your own tuning. This is where the Innovate Motorsports LM-1 comes in. Nightrider.com Performance Products is now offering the LM-1 and other tuning/data logging/monitoring components.

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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

Where is Sifton Cams?

Autocom Active-7 tested

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