Yamaha TRX850 Enthusiasts Forum

I personally use a megasquirt2 ECU for my ignition setup, but this could possibly be an option for some to get a new curve rather than it being fixed. I have no real information on it, but i chat daily with another group who are building a new ECU, and im probably going to be the test mule for it. Its going to be a 100% open-source and free (as in freedom to do what you want) and do some fairly cool things.

http://secu-3.narod.ru/index-en.html

I dont expect anyone to ever get one, but it does show that options are out there for total retuning of their ignition curve.