ItÂ’s All About The Fun. fuel injected, 125cc, single cylinder air cooled, 4 gear, fuel injection.Reduced size, increased fun125cc Fuel-Injected Engine. Nobody can match HondaÂ’s reputation for engines, and even though the Grom may be compact, itÂ’s a giant in terms of performance and reliability. 4 Gear Transmission. The GromÂ’s 4 gear transmission gives you all the durability, control and efficiency of a conventional motorcycle. Hydraulic Disc Brakes. The Grom features excellent 220m front and 190m rear single disc brakes for stopping power. Multi-Function Digital Instruments. Instrument display features speedometer, odometer, tachometer, A&B trip meters, fuel gauge, clock, and indicator for low/high beam.