The MTNTK “FIX KIT” or “DURABILITY KIT” is the proven solution to the piston failure that is common in the 2008 to 2014 POLARIS 800 engine. The failure is caused by the piston clearance in the cylinder being loose and allowing the pistons to rock in the cylinder bore. With that rock or “piston slap” the pistons scrape the cylinder wall and remove the oil film from the cylinder wall. As the pistons continue to scrape they begin to cause damage to the pistons, rings, and the cylinder. “Piston slap” also causes the pistons to develop a knifed edge and the piston skirts/cylinder skirts to fatigue. As this happens the engine will begin to loose compression and begin experiencing “bog” issues, and as it worsens it will begin to idle poorly and not switch into reverse. The engine failure can take time and show all of these signs or can go quickly without notice. The MTNTK “FIX KIT” is designed to eliminate the piston slap issue. By adding a cylinder shim it allows us to increase the height of the piston which dramatically reduces the piston’s tendency to rock in the cylinder bore. The “FIX KIT” also tightens up the clearance in the cylinder, and by so doing increases the durability of the 800 motor, while increasing compression thus increasing power. Fueling modified engines: If you choose to add any other aftermarket products (IE: cans, pipes, power commanders) you will need to contact the aftermarket company you purchased the product from for their recommended flash for their products. The “FIX KIT” is compatible with most aftermarket products as it does not change the functionality of the engine much from original equipment. Proper tuning checks should be made by a competent engine tuner.