Has done research comparasion of usage CDI for knowing the effect of different type CDI Standart and CDI BRT I-Max with usage of premium fuel + ethanol as much as 2% to sparks characteristics and performance motorcycle of Supra 125 cc 4 step manual transmision in 2008. This research done to know the effect of ignation system on performance or consumption of fuel. Sparks testing on spark plug tested using a test tool which makes use of ratotion elecric machines as big as 3000 rpm. Torque and power are tested using a dynotest tool of engine speed of engine speed of 4000-10,000 rpm, while for testing fuel consumption is done by testing the rood at speed ±40 km/h far as 4 km/test with fuel dose. From the results of the researh, the best spark on the variation of CDI BRT I-Max with Spark Iridium because the spark are constan with a temperatur of 8000-9000 Kelvin. The largest power isto the test result of spark obtained on CDI BRT variations with Iridium spark plug at round 6795 rpm with power of 10,02 HP. Highest torqeu of 12,72 N.m at round 4949 rpm CDI BRT variations and spark Iridium. While the most economical fuel consumption on CDI BRT I-Max variation with spark plug with at range if 52,08 Km/liter