We've been designing and building Big Bore kits for 40 years. Our Kawasaki big bore kits can produce as much as 30% more displacement and 30% more torque. The best thing about a Kustom Kraft big bore kit is that they are the most reliable method of increasing horsepower. The powerband remains well below red-line and most of the increase in horsepower is in the lower rpm's.Reliability is the name of the game. If you can rebuild a top end you can do the big bore kit. Here's how it works. In the case of most 2 strokes tear down the top end and send us the cylinder, cylinder head, and exhaust valves if any. For 4 stroke models all we need is the cylinder. Be sure to print out the job order form and fill it completely. Carefully pack your parts so they don't get damaged in shipping. Send them to us along with the order form. We will bore out your cylinder and re-plate it or sleeve it as needed. We supply all the special big bore parts such as piston kit and gaskets when needed. Complete instructions will be included.