For an air/fuel ratio device that you can keep on the bike or just plug in for testing, the Halmeter has been the best I have used thus far. It is far more accurate than the K&N style units. Provided in the kit is a threaded bung that you would weld to the pipe after the collector. The O2 sensor would find home there. This device retails in the high $200's and is a real nice tuning tool. BUT.... without the ability to "peak hold" or "playback" you need to view the results in realtime. A dragstrip is the safest palace I can think of for full throttle testing! The mightly "busa eats up some real estate real quick to have yor eyes of the road for too long!
The design of the lambda or oxygen sensor provides a signal which is easily interpreted by the Halmeter AF30. The sensor produces a small voltage outout by comparing free oxygen in the exhaust gases with ambient oxygen outside the exhaust system. This voltage is created when the sensor is heated to between 360 degrees centigrade (680 F) and 900 degrees centigrade (1650 F) and varies between zero and one volt. The AF30 processes this voltage output and displays the result via a series of red, yellow and green LEDs: the red lights for lean, yellow for the stoichiometric band and green lights indicating mixtures likely to produce maximum power. It should be noted that, in the event the sensor is located in the exhaust where the temperatures are at or above the maximum, a reduced voltage output will result in fewer lights in the green band being lit at rich mixtures.
Dividing the small output from the sensor into thirty incremental LED's gives the Halmeter AF30 superior resolution compared to other instruments of its type.
The Halmeter AF30 Air/Fuel Ratio Indicator offers the tuner a low cost, attractive unit with thirty LED indicators that signal lean-optimum-rich.
The HalmeterAF30 Air/Fuel Ratio Indicator works on all engines, carbureted or injected, and with gasoline, alcohol or propane fuels. When used with programmable EFI systems, it helps establish fuel maps and makes the mixture trim control a more precise tool for on track tuning.
The Halmeter AF30 Air/Fuel Ratio Indicator kit is supplied complete with meter, wiring harness, oxygen sensor and exhaust fittings.