I have a 2005 CRF250R engine in a 1994 Honda RS125 roadrace chassis I built for Land Speed racing at Maxton Mile. I added a small shot of Nitrous to it in Sep 2010 with great success. But as I start to add more this year I need to retard the timing 3-5 deg. Does anyone know how I can do that? Did I miss it in the manual? I use the stock ICM. Thanks.