A 49mm Nikasil cylinder and piston kit for the Stihl MS311, taking the saw from its stock 47mm bore to 49mm. The kit contains the Nikasil-plated cylinder, a 49mm piston, piston rings, wrist pin and circlips. This is the 3-bolt intake version: these cylinders were built with both 3-bolt and 4-bolt intake manifolds, so count the bolts holding the intake to your old cylinder before ordering. It replaces cylinder assembly 1140-020-1204. If you want a straight repair at the original 47mm size, look for a 47mm MS311 piston instead. Before fitting, pressure and vacuum test the crankcase and replace hardened seals, a cracked intake boot or a split impulse line, since an air leak scores a new piston as fast as the old one. Use a ring compressor on assembly, and check the carburetor setting once the saw is run in, because the larger bore draws more fuel.
- 49MM BIG-BORE CYLINDER AND PISTON FOR THE STIHL MS311 - Takes the MS311 from its stock 47mm bore to 49mm. The kit holds a Nikasil-plated cylinder, a 49mm piston, rings, wrist pin and circlips.
- COUNT THE INTAKE BOLTS FIRST - This is the 3-bolt intake version. These cylinders were made with 3-bolt and 4-bolt intake manifolds; count the bolts on your old cylinder before ordering. It does not fit a 4-bolt saw.
- WANT THE STOCK 47MM SIZE INSTEAD? - This kit changes the bore. For a straight repair at the original size, a 47mm MS311 piston is the part to look for.
- REPLACES CYLINDER ASSEMBLY 1140-020-1204 - The 49mm cylinder and piston assembly. If your parts list shows this number, match the intake bolt count before ordering.
- BEFORE THE NEW TOP END GOES ON - Pressure and vacuum test the crankcase and replace hardened crankshaft seals, a cracked intake boot or a split impulse line. A larger bore draws more fuel, so check the carburetor setting once the saw is run in.