<![CDATA[Purposes of the research are: (1) Knowing effect of ignition booster application on exhaust gas emission of CO and HC of Honda Supra X 125 2007 motorcycle; (2) knowing effect of methanol addition in premium fuel on exhaust gas emission of CO and HC of Honda Supra X 125 2007; (3) knowing interaction of effects of ignition booster application and methanol addition in premium fuel on exhaust gas emission of CO and HC of Honda Supra X 125 2007.The research is performed in Laboratory of Machine Engineering Education of Teacher Training and Education Faculty of Sebelas Maret University of Surakarta. The research uses experiment method in attempts of knowing exhaust gas emission of every experimentation treatment. Sample of the research is Honda Supra X 125 2007 motorcycle with machine number: JB51E1941073. Sample is taken by using purposive sampling technique by taking one sample of motorcycle, namely Honda Supra X 125 2007 from population of typical Honda Supra X 125 2007 motorcycles. Data analysis of the research is a statistical analysis by using 4 x 4 Two-Way Anava.Results of the research were: (1) There was effect of ignition booster application on exhaust gas emission of CO and HC of Honda Supra X 125 2007. It is indicated by result of CO data analysis showing Fobservation= 49.04 > Ftable = 4.46 and result of HC data analysis with Fobservation = 11.01 > Ftable = 4.46 at significance degree of 1%; (2) There was effect of methanol addition in premium fuel on exhaust gas emission of CO and HC of Honda Supra X 125 2007. It was proved by results of CO data analysis test with Fobservation = 940.51 > Ftable = 4.46 and results of HC data analysis showing Fobservation=19.90 > Ftable = 4.46 at significance degree of 1%; (3) There was an effect interaction of ignition booster application and methanol adding in premium fuel on exhaust gas emission of CO and HC of Honda Supra X 125 2007. It was indicated by result for CO data analysis showing Fobservation=11.10 > Ftable = 2.94 and for HC was Fobservation = 20.97 > Ftable = 2.94 at significance degree of 1%.]]>
