TRX 2.5 Racing Engine comes loaded with all the hottest performance goodies Two-needle composite slide carburetor, trick porting, and free-flowing rear exhaust deliver unmatched horsepower TRX 2.5 has the option of push-button starting convenience of the EZ-Start Electric Starting System TRX 2.5 Racing Engine uses a high-volume air intake system with a two-stage air filter Filter housing and neck are designed to eliminate turbulence in the air-flow going into the engine Knife edge connecting rod Long rod design Super light piston and rod Square reciprocal geometry High performance ball bearings