The Banshee center case had a substantial mismatch at the cylinder base. The step was ground out so the air will transition smoothly from the crankcase into the transfer tunnels at the bottom of the cylinders. Removing the step is good for about 2 hp. Cylinder porting makes the Banshee a lot more fun to ride. There are various porting methods used to make power. This is critical when it comes to an engine build. Make sure you tell the engine builder what you use the quad for so you get the proper porting. For duneing, you need a useable powerband. This is accomplished by shaping and angling the transfer ports to more effectively fill the combustion chamber. The transfer ports are angled so the fuel charge emerges from the transfers and forms a coherent column of gas that sweeps back toward the rear cylinder wall and sweeps up the back of the cylinder walls to the spark plug. This column of gas scavenges the residual exhaust gas out of the cylinder without allowing it to mix with the new charge. This design also helps hold more fuel in the combustion chamber at low rpm. This prevents the fresh fuel charge from short-circuiting out the exhaust port and being wasted before it can be burned in the combustion chamber. Preventing this loss of fuel charge at low rpm will dramatically improve bottom and midrange power needed for duneing. This is key to why LRD's engines are famous for making big horsepower while retaining strong, useable, low-end power. The exhaust port is also reshaped for better breathing. Added boost ports are put in the intake port. To further improve performance, the cylinder is bored by 1 mm to slightly increase engine size to a 65mm bore. The piston receives a dry film lubricant coating to the skirt to reduce friction and increase part life. A thermal barrier coating is baked to the top of the piston which improves piston life by reducing piston temperatures. This also keeps the heat on the fuel which allows more fuel to be used. This of course also enhances performance.