02-19 YAMAHA YZ250: FMF Powercore 2 Shorty Silencer - 2-Stroke Taking the proven success of the Powercore 2, FMF created the Powercore 2 Shorty, with a shorter inner core length and aluminum canister. This design results in a finely tuned bolt-on performance silencer that maximizes bottom and mid-RPM power.An excellent choice for tight tracks and supercross track applications.The Powercore 2 Shorty silencer has a shortened inner core length and caniste Not intended for street use.