I found my notes and typed them up because even I could barely read my chicken scratches. As I said, I’ve done the Power Commanders and Fuel Paks and older SERTS, but never used the Master Tune. The shop I was at had a Dyno 250i so I never had to install one with a laptop bungeed to the seat, but it seems to me that you should be able to get pretty good results even though it might take a little longer. It looks like it will be fun and you’ll save the cost of a dyno tune!
Okay, these are from a few years ago:
(Run the software updater to make sure you have most current updates!)
1. Connect to the 4 pin HD data port. (You can use an older SERT or SEST cord.)
2. Save the factory ECM calibration to file
a. Start Master Tune-HD
b. Choose menu item “File/Save or Restore Factory Calibratin.”
c. Get ECM info
d. Choose “Command / Save ECM calibration.”
3. Use Master Tune-HD to choose and install the closest starting calibration from the MT files. Use Master Tune Cal File Listing to locate.
a. Start Master Tune-HD
b. Choose base tuning file to be installed.
c. Choose “File/Program ECM” menu item and install the base tuning file to the ECM. (I’m guessing you’ve already gotten this far, yes?)
4. Start engine and warm up.
5. Use DataMaster to record VTune Data
a. From the File menu, choose “Record VTune Data”
b. Choose filename to write data to. Default name is easy.
c. Test the interface with “Get ECM Info.” If you can get ECM info you have good commo.
d. Record the tuning data.
Secure the computer and take a short ride. (Make sure it doesn’t go into sleep or hibernation mode when you close the top!)
Accelerate slowly and smoothly, don’t goose it.
Ride through as full a range of throttle conditions as you can, but no sudden accelerations.
Don’t shut off the bike until you stop recording data.
6. Use VTune to generate a new calibration map.
a. Launch VTune.
b. Select the calibration file loaded in the ECM and the VTune data file recorded in the last step and “Generate Tune.”
c. The new calculated VE tables for front and rear cylinders will display indicating a range of calculated changes.
d. Choose “Accept” and generate the new calibration file.
e. Install the new calibration file into the ECM as in step 3 above using MasterTune.
7. Do it again! Record new VTune Data with DataMaster-HD (step 5 again), and use VTune-HD to calculate new calibration (Step 6 again). When the new VE tables are displayed, hit “Accept” and generate a new calibration file. Each time the changes should be smaller. Install, record again and recalculate again. You will likely have to do a total of at least 3 times.
I didn’t write down what version this was for but I want to remember it was for a MT6? 7? If you have a newer version they have likely added a bunch more bells and whistle, but the basic process should be about the same so maybe this will get you close. I’d think it should but like I said I’m not a Master Tune guy. (A lot of people love them though.)
Also, some of the newer Big Twins now use Lambda values instead of AFR data but your Sportster hopefully hasn’t changed to that yet. It’s no big deal if your tuner will read it correctly, but it makes it harder to look at a VE table and get an idea of which cell might be lean or rich so you can adjust by eye. Lambda numbers mean absolutely nothing to me!
Hey, let me know how it works out for you!