A 49mm cylinder and piston kit for the Husqvarna 460 and 460 Rancher, the 455 and 455 Rancher, and the Jonsered CS2255. The kit contains the cylinder, piston, piston ring, wrist pin, wrist pin needle bearing and circlips, with installation instructions. Gaskets and crankshaft seals are not included. It replaces part number 537320501 and the earlier 537320402. The 460 is a 49mm, 60.3cc saw from the factory, so on a 460 this is a straight replacement. The 455 left the factory at 47mm; on a 455 this kit is the big-bore upgrade, and because the cylinder and piston come together as a matched pair it replaces the original top end as a unit. Before fitting, pressure and vacuum test the crankcase and replace hardened crankshaft seals, a cracked intake boot or a split impulse line, since an air leak scores a new piston as quickly as it scored the old one. Fit a new base gasket, tighten the cylinder screws evenly, and check the carburetor once the saw is run in.
- CYLINDER, PISTON AND THE SMALL PARTS - A 49mm cylinder with its piston, piston ring, wrist pin, wrist pin needle bearing and both circlips, plus installation instructions. Gaskets and crankshaft seals are not part of this kit.
- FITS HUSQVARNA 460 AND 460 RANCHER, 455 AND 455 RANCHER, AND JONSERED CS2255 - The 460 is 49mm from the factory. On the 455, which left the factory at 47mm, this kit is the 49mm big-bore upgrade: cylinder and piston come as a matched pair and replace the whole original top end.
- REPLACES PART NUMBERS 537320501 AND 537320402 - 537320501 is the current number and 537320402 the earlier one. If the parts list for your saw shows either number for the cylinder assembly, this kit covers it.
- MEASURE THE OLD PISTON FIRST - A 460 piston measures 49mm and a 455 piston 47mm. Either way the new cylinder and piston go on together: never fit this 49mm piston into an original 47mm 455 cylinder.
- 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. An air leak leans the mixture and scores a new piston the same way it scored the old one. Use a new base gasket and tighten the cylinder screws evenly.