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Off Road motorcycle Fuel Injection 101


Eddie Sisneros

The intent of this article is to give a general over view of current off road motorcycle fuel injection. There are alot of myths and misunderstand regarding fuel injection in this realm of usage.

Lets start with what fuel injection can and cannot do as far self compensation. It cannot compensate for any change in flow. Regardless of intake/exhaust changes,fuel type or engine mods the ECU will contiuinue control the fuel and ignition as if it were stock. There is no sensor that monitors flow. What it can do is compensate for elevation (barometric pressure sensor) and air temperature (intake air temperature sensor). If the base fuel and ignition map are correct and the bike runs perfect in one condition,it will also run perfectly as the conditions change.

The reality of the situation is just like stock carburetor jetting isnt perfect neither is the stock fuel injection mapping. Until the manufactures update the systems to use oxygen sensors and/or air flow meters it will be up to the end user the correct the fueling and ignition for the specific modifications done and conditions/situations they are used in. Fueling is corrected for flow changes. Ignition timing is altered to tailor the power delivery and to take advantage of low grade or high grade fuel.

So how do you go about tuning your fuel injected motorcycle? You first need to purchase/aquire the fuel injection tuning device you desire or use the services of a tuning specialist such as my self or several others. If you intend to do your own tuning you will also need to invest in a wide band air fuel ratio meter. With out a wide band air fuel ratio meter you will be just guessing and may as well be blindly pounding on the key board.

Once you have the fueling correct you can move on to altering ignition timing to change the power delivery. You must have a device capable of altering the ignition. Currently only the OEM flash tuner offer this option. All other "piggy back" tuners are not currently capable of controlling the ignition. The "piggy back" tuners do however offer much more friendly and quicker to use. The ultimate way to tune is via the use of the OEM flash tool to control the ignition and "piggy back" tuner to control the fuel. This may be cost prohibitive for most end user unless you enlist the service of a specialist. In that case you don't actually buy the OEM flash tuner.

If you are lucky enough to live near or able to travel a to a capable tuning specialist they can tune your motorcycle on a dyno. This is the most accurate method. However a reflash via mail or purchasing a tuning device with a

pre loaded map for your specific set up can work very well.

In the next installment i will cover the capabilities of the different tuning devices on the market and pro's and con's of each.

Eddie Sisneros



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