I just did this on my new race bike, twpd. After quite an exhaustive search, I chose the AIM Mychron 3 Gold which has 4 analogue channels. I use them for throttle position, airbox pressure, exhaust temp, and lambda. As I am sure you'll know, to measure A/F ratio you need a wide-band lambda sensor and an amplifier to produce a 0-5 V signal that you can log. Most of these are for cars and tend to be quite big and far more complicated than you really need. I got my sensor and amplifier from an Oz company (
http://wbo2.com/2c0/default.htm). It's simple, small, and reasonably price.
If you want further details, send me a U2U.
Hybrid Mode
