The next feature is a new tuning process that allows you to tune the low throttle area using the bikes standard narrow-band O2 sensors.
The narrow-band sensors are only accurate at 14.7/1 A/F ratio; this is no use if you want to tune the motor to run at 13.2/1 but we now have a way around this.
The process is to use the narrow-band sensors to correct the low throttle area to run at 14.7/1. Once this area has been corrected to 14.7/1 we can use a % adjustment to bring the mixture down to 13.2/1.
These are the steps required:
Start the latest TuneBoyTrim program and set the AF target TP screen so it has an area showing 14.70 (See image below). No adjustments will be made unless the target is exactly 14.70.
Press the 'T' key to show the target screen and select "NarrowBand0-1.2v" as the O2 sensor type.
Start the motor and let it warm up.
Now press the 'a' key on the keyboard; this will turn on the auto-tune mode and you will see a dot next to "Auto tune enabled" in the target window. If you don't see the dot press the 'a' again as sometimes it does not turn on first time.
Once the auto-tune has been turned on the program will start to adjust the "Fuel TP Trim" (F) and (R) tables to try and reach 14.7/1
Once the A/F crosses 14.7/1 four times the TuneBoyTrim program will mark the point in the table as being correct. The colour of the A/F value will change to yellow.
If you put the laptop in your backpack and ride the bike you should be able to get most of the low throttle area to have yellow squares. It is a good idea to mark the throttle points on the throttle grip with correction fluid (Liquid Paper) and a pen. Using this method you know how far to turn the throttle so you collect good data.
To increase the hit rate for the A/F values you can adjust the size of the green square and decrease the sample count. The size of the green square is adjusted by going to the "Tools" and "Process log file". On this screen you can change the "RPM and throttle zone %" to a larger number, something like 40 or 45. This will collect more data.
You can also reduce the "Stable throttle for number of samples" to make it collect data sooner.
Once you change these values just click "Cancel" on the progress log screen. The values will still be changed in the target screen.
A good process would be to increase the target zone to 45 to "rough tune"; this should get the values close.
After this you should save the trim file and stop and start the TuneBoyTrim again. This time, leave the target zone set to 20. When you stop and start the program the yellow squares are reset but it should not take long for them to turn yellow again as the trim should be correct for 14.7/1
Once you are happy with the number of cells that are turning yellow you can move to the next stage.
Save the trim file with a new name so you keep a copy of the trims required to get 14.7/1.
In the new trim file you can change the AF Target TP values back so they range from around 13.2 at the bottom and get richer as the throttle increases.
Now you can select the cells in the "A/F TP" (F) and (R) tables and press the 'c' key. This will calculate the trim required to move the A/F from the 14.7 value to the new value in the target screen.
If you need to retune the low throttle area you should use the trim file you saved before doing this final correction.
Keep in mind that any cells that did not turn yellow could become too rich if you include them when you do the final correction. This is why it is better to take your time and get as many cells to turn yellow as you can.
I hope to have an iPhone app that can do the adjustment while riding. This will make it easy to see throttle position and should speed up the process.
Stay tuned!
