Hello all. After several months of messing with this, I have learned how to communicate with the Mikuni ECU without having to use iBeat. At this point, it is very clunky, but it works. I am working on some YouTube videos to explain, and an Android app to make it easier, but for now I figured I would post what I have learned. Unfortunately, it is only 15 years too late!! This got really long, too long for a post, so I just uploaded a document. I am still working on sorting out some additional parameters. If you have iBeat already, this is not an upgrade. It's biggest advantage I see is that if you want to test different CO settings you can do it on the fly without a laptop. I am working on an embedded controller that will facilitate the use of bluetooth. It will also make it easier to use both Android and iPhone. Right now I have only tested with Android. In this process, I have also built (on a breadboard, very janky) a serial to K-line converter using a 30 cent IC (LM2903 for you nerds) and a few resistors. This is beneficial is you want to build something to talk to your bike through some kind of controller. Or if for some reason the USB to K-Line adapters become hard to get or more expensive. But if you have a working cable and going to connect to the with something that has a USB port (which includes smartphones) then just keep using that. Sorry this is coming so late after these bikes were made. Edit- Rev 1.1 added 2/21. Includes error codes and a table of percentage from 95 to 150 with their Hex codes. Makes it easier to reference CO values.
The real short-coming to iBeat was it was still seat of the pants evaluation. Software that measured AFR was less subjective. Congrats on cracking the code.