This system is different in it's method of
adjustment by dealing directly with the fuel injection signal after it leaves
the factory ECU. It adjusts your fuel requirements without tricking sensors or
modifying the factory settings which can limit the ECU's effectiveness at
compensating for changing altitude or weather conditions.
The digital circuitry construction allows a
specific range of adjustment of the fuel delivery curve in the areas that most
effect drivability and performance.
Idle/Cruise: As fuel injection is very
efficient, it considers idle and cruise to be virtually identical as far as
their A/F ratio requirement goes (as opposed to carburetion), so the low speed
adjuster (Green Adjustment Screw) can be set similar to an idle mixture screw on
a carburetor. As the motorcycle accelerates under light to medium load, the ECU
maintains an A/F ratio consistent with its emissions focus, and the TFi box
makes slight modifications to that focus based on your drivability requirements.
Midrange: With fuel injection midrange
fueling is only relative to fast acceleration at or near full throttle. At
certain speeds and loads as the factory ECU makes transitions between cruise
and performance A/F ratios. Using the yellow adjustment screw and the RPM select
adjustment the TFi box has the ability to select and alter fuel at these points
of transition. This effect is similar to the effects that a needle position
change and an accelerator pump can have in a carburetor.
Main/Top End: Once the throttle is opened
abruptly or an engine RPM/load is achieved that demands a performance bias A/F
ratio, the main fuel adjuster can come into play. (Red Adjustment Screw) Similar
to carburetion, air filters, race exhaust, cams, etc. can effect the fuel
requirements in the performance range. The main fuel adjuster can compensate for
these types of modifications just like changing a main jet in a carburetor.
