Gmp ,
l have a 05 ec 250 ,it had the dual cdi on it but no switch , l put a switch on it about a year ago , the sunny mode
feels like the motor has been leaned off a bit , it is a fair bit crisper and has a slight but noticable crack to it , l like using this setting on open courses when its really muddy as the rear spins up quicker and seems to clear the rear wheel and grip , the rain setting mode ( handbag mode ) is pretty helpful when going gets tricky , slippy uphill climbs are a little better , on the whole the effect of the switch is quite suttle , worth having if you have the dual cdi fitted already , just for the record l also tried the bigger power valve cover but l found it had too much bottom end and took it off after one race
, hope this of some help
