The most economical and effective way to increase the performance of your engine. Available for two stroke
and four stroke Motorcylces 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.

Kustom Kraft Performance Big Bore Kit
Honda Motorcycle and ATV kits
Kawasaki Motorcycle and ATV Kits
KTM Motorcycle Kits
Suzuki Motorcycle and ATV Kits
Yamaha Motorcycle and ATV Kits
*Click below for prices and application list of available Big Bore Kits*

AMA competition bulletin:
amateur motocross class rules changes governing big bore kits
Product Review
Independent Test of KLX 250S KK 330cc Kit
Kustom Kraft Performance KTM Big Bore Kit
Motorcycle-ATV-Personal Watercraft-Snowmobile

2 Stroke-4 Stroke-Dirt Bike-Street Bike

A Kustom Kraft Big Bore kit 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.


See KLX250 Dyno test Here