Cylinder and piston kit for the Husqvarna 372XP X-Torq and 365 X-Torq. 50mm bore. Replaces 575255702. X-TORQ ONLY - READ THIS BEFORE ORDERING This kit is for the X-Torq versions of these saws. Part number 575255702 is the X-Torq cylinder kit number. FITS 372XP X-Torq, including the G and W versions 372 X-Torq and 372 XT 365 X-Torq and 365 XT CS2166 and CS2172 All of the above are 50mm. DOES NOT FIT The earlier non X-Torq 371XP and 372XP. Those take cylinder and piston assembly 593665504, which supersedes 503626473. The earlier non X-Torq 365, which is a 48mm bore, 65cc engine and uses 503939071. THE 365 IS WHERE THIS GOES WRONG MOST OFTEN Husqvarna changed the 365 when it went X-Torq. The earlier 365 is 65cc with a 48mm bore. The 365 X-Torq is 70.7cc with a 50mm bore, the same as the 372. So a 50mm kit fits a 365 X-Torq and does not fit an earlier 365. You will see this kit listed elsewhere as fitting the 365 with no qualifier, and you will see the 50mm pre X-Torq assembly listed as fitting the 365 as well - those are big bore upgrade fitments, not replacements. Go by your own saw. SPECIFICATION Bore - 50mm Displacement - 70.7cc RELATED NUMBERS 575255702 - X-Torq cylinder and piston kit, this one. Also seen as 575255701 and 575255703 across revisions, and cross referenced to 575774101, 575774102 and 575774103. 593665504 - non X-Torq 371XP and 372XP assembly, 50mm, replaces 503626473 503939271 - non X-Torq piston only, 50mm 503939071 - non X-Torq 365 cylinder kit, 48mm HOW TO IDENTIFY YOUR SAW The X-Torq name appears on the cylinder cover and in the model designation on the rating plate. Look for 372 XP X-Torq, 372 XT, 365 X-Torq or 365 XT. On a 365, bore alone settles it - 50mm is X-Torq, 48mm is not. On a 372, both generations are 50mm, so use the model designation and the cylinder casting rather than the bore. If you are still not sure, measure the bore and tell us what the plate says and we will tell you which kit you need. BEFORE YOU ASSEMBLE Work out why the old top end failed. Scoring on the exhaust side means lean running or an air leak, and the new cylinder will score too if the cause is still there. Pressure and vacuum test the crankcase and do not skip this. Replace both crankshaft seals if they are hard or there is any doubt. Check the intake boot for cracks. Clean both base gasket faces back to bare metal. Check ring end gap in the new bore. Fit the circlips with the opening away from the ports and make sure both seat fully.
- X-TORQ MODELS ONLY - THIS IS THE ONE THING TO GET RIGHT - Replaces 575255702, which is the X-Torq cylinder kit. Fits 372XP X-Torq, 372 X-Torq, 372 XT, 365 X-Torq and 365 XT, plus the matching CS2166 and CS2172 units. It does NOT fit the earlier non X-Torq 371XP or 372XP, which take 593665504. If your saw is pre X-Torq, this is the wrong kit.
- THE 365 IS THE TRAP - The earlier 365 is a 65cc engine with a 48mm bore. The 365 X-Torq is a 70.7cc engine with a 50mm bore. Husqvarna raised the displacement when the 365 went X-Torq, so saying a part fits a 365 means nothing without the X-Torq qualifier. That is a 2mm difference in bore and a completely different cylinder. Read the saw before you order.
- 50MM BORE, 70.7CC - Both the 372XP X-Torq and the 365 X-Torq are 70.7cc on the same 50mm top end, which is why one kit covers both. Supplied as the cylinder and piston together, so you are not matching a new piston to a worn bore.
- HOW TO TELL AN X-TORQ - X-Torq saws carry the X-Torq name on the cover or in the model designation, and the model plate will read 372 XP X-Torq, 372 XT, 365 X-Torq or 365 XT rather than plain 372XP or 365. If the plate is missing or unreadable, measure the bore - 50mm is X-Torq on a 365, 48mm is not. On a 372 both generations are 50mm, so on that saw go by the model designation and the cylinder casting rather than by bore.
- BUILD IT PROPERLY - Find out what killed the old one first. Scoring on the exhaust side is lean running or an air leak, and a new cylinder in the same conditions goes the same way. Pressure and vacuum test the crankcase, replace both crank seals if there is any doubt, check the intake boot, and clean the base gasket faces down to bare metal. Check ring end gap in the new bore before you close it up.