TNT aluminium replacement cylinder kit for air-cooled Yamaha 125cc engines (mostly used before 2006, but some still used today). Especially when the original cylinder is worn out or loses performance due to age and high mileage, a replacement of the complete kit is the easiest way to get back to a good function. The TNT cylinder is supplied with seals, pistons and piston rings. The cylinder head must of course be reused. However, you should check if the head is still flat before assembly. If not, it should be reworked by an engine specialist.