If you’re looking for a big bore kit, this one from KOSO is the way to go. It includes a ceramic coated cylinder, 61 mm forged piston, rings, pin and a full gasket set to bump your Honda Grom up to 170cc. Grom big bore kit also features a dual overhead cam design, and the compression ratio is set up for premium pump fuel.

Can you big bore a Honda Grom?

The cylinder is coated in SiCl, which is extremely hard and durable, and it’s electroplated with NiSi to prevent any corrosion issues. This combination provides the best heat dissipation possible for your 125cc engine. The cylinder’s interior is also treated with silicon carbide, which helps the cylinder walls resist heat and reduce friction for increased power.

Before installing the new cylinder, you should make sure that the crankcase mating surface is clean and that the timing marks are correctly aligned with the mark in the cylinder head. This will ensure that the valve lash and the air/fuel mixture are properly adjusted for maximum performance. Watch the cylinder installation segment of our Honda Grom Big Bore Kit video to see how to do this.

Whether you’re riding your Honda Grom on the street or at the track, a big bore kit will add some serious fun and power to your bike. The more torque you have, the faster you can get up to speed and turn in on a tight corner. If you’re into racing pit bikes, more power will level the playing field with other competitors on the same bike.