Big Bore kit by Kustom Kraft Performance is the least expensive way to increase overall performance. There is no substitute for displacement. An increase in displacement is directly related to torque. Unlike other engine modifications there is no sacrifice in power on one end on the power band for the sake of the other end. The big bore kit will increase both torque and horse power over a broad range. Our reliable bore kits offer huge increases in torque for great low end and increased power through out the entire power band. No other modification can deliver the performance like a genuine Kustom Kraft Big Bore Kit.

The most economical and effective way to increase the performance of your engine. Available for two stroke and four stroke Motorcyles and ATV's a like. Whether racing or just trail riding, increasing your engine displacement with a big bore kit will give you that added power you've been searching for. Big bore kits are very reliable and easy to install when compared to most other engine modifications. We carry big bore kits for all the popular brands and most come with Wiseco, ProX, or JE racing pistons and gaskets. Send us your cylinder and head (two stroke cylinders only) along with the power valves, we will bore, sleeve or Re-Nikasil your cylinder to the new larger size. Your power valves will be modified if needed to function properly with the larger bore size. Some models will have the cylinder head re-chambered for the proper volume and compression ratio. Our big bore kits include a high performance piston with piston rings, piston pin and circlips. New top end gaskets are included for most models.