50mm Cylinder Kit 1.5mm Ring Fits Husqvarna 371XP 372XP

50mm cylinder and piston kit that fits the Husqvarna 371XP and 372XP with the earlier 1.5mm-ring engine, supplied with the top-end gasket set and the bearing. Replaces 593 66 55-02, which supersedes 503 62 64-73. IN THE BOX: 50mm cylinder with the decompression valve on top, 50mm piston with rings, piston pin and circlips, top-end gasket set and bearing. NOT INCLUDED: crankshaft seals, which are worth fitting while the engine is open. HOW TO TELL WHICH ENGINE: both versions are 50mm and 70.7cc, so neither bore nor displacement separates them. The ring does: 50 x 1.5mm takes this kit, 50 x 1.2mm is the later engine and does not. The later engine also has a recoil-cover decal and a different intake, and its assembly is 575255702. NOT THE 365 OR 362XP: the original 365 is 48mm at 65.1cc and the 362XP is 47mm at 62.4cc; the later 50mm 365 takes the later cylinder. On assembly, check ring end gap in the new cylinder, use a ring compressor and fit the circlips with the open end away from the ports.

• 50MM TOP END WITH GASKETS AND BEARING - Cylinder, piston, rings, piston pin, circlips, top-end gaskets and the bearing. Replaces 593 66 55-02, which supersedes 503 62 64-73. The cylinder carries the decompression valve on top. It is not 575255702, which is the later engine's assembly.
• FITS HUSQVARNA 371XP AND 372XP WITH 1.5MM RINGS - Both versions of these saws are 50mm and 70.7cc, so a caliper cannot separate them. The ring can: a 50 x 1.5mm ring is the earlier engine and takes this kit; a 50 x 1.2mm ring is the later engine, which takes a different cylinder. The later engine also has a decal on the recoil cover and a visibly different intake.
• NOT FOR THE 365 OR THE 362XP - The original 365 is a 48mm saw at 65.1cc and the 362XP is 47mm at 62.4cc. Neither takes a 50mm assembly, whatever a cross-reference list says. The later 50mm 365 runs the 1.2mm-ring engine and takes that cylinder, not this one.
• WHAT IS IN THE BOX - Cylinder, piston, rings, piston pin, circlips, the top-end gasket set and the bearing. Crankshaft seals are not included and are worth fitting while the engine is open, because a hardened seal leans the mixture out and takes the new piston with it.
• BEFORE ANYTHING GOES TOGETHER - Check ring end gap in this cylinder rather than the old one, use a ring compressor, and fit the circlips with the open end away from the ports. This is a stock replacement; if you are building for compression, measure squish with solder through the plug hole.