50mm Pop Up Piston Kit Fits Husqvarna 372XP 365 XT 1.2mm Ring

Raised-crown 50mm pop-up piston kit, with rings, wrist pin and circlips, that fits the later Husqvarna 372XP and 365 XT chainsaws, the 70.7cc engines with a 50 x 1.2mm ring. The earlier 371XP and 372XP with a 1.5mm ring take a different piston, and the earlier 365 is a 48mm saw. The raised crown reduces combustion chamber volume and raises compression, giving more low-down torque and easier starting, but it does not reliably add peak power on a stock cylinder. Measure squish clearance with solder through the plug hole before running it, and do not delete the base gasket as well. Use a ring compressor, seat the circlips with the openings away from the ports, and pressure and vacuum test the crankcase before the first start.

• FITS HUSQVARNA 372XP AND 365, LATER XT SAWS ONLY - A raised-crown pop-up piston kit, with rings, wrist pin and circlips, for the 70.7cc engines with the 50mm bore.
• THE RING TELLS YOU WHICH SAW YOU HAVE - A 50 x 1.2mm ring is the later XT engine and takes this piston. A 50 x 1.5mm ring is the earlier 371XP and 372XP engine, which takes a different one. The earlier 365 is a 48mm saw and does not take it at all.
• WHAT A POP-UP DOES - The raised crown reduces combustion chamber volume and raises compression, which gives more low-down torque and easier starting. It does not reliably add peak power on a stock cylinder.
• MEASURE SQUISH BEFORE YOU RUN IT - A raised crown uses up squish clearance. Check it with solder through the plug hole, turning the engine through top dead center by hand, and do not delete the base gasket as well: the two changes stack and the crown can reach the head.
• ON ASSEMBLY - Use a ring compressor, fit the circlips with the open end away from the ports, check ring end gap in the bore, and turn the engine over by hand before the first start. Pressure and vacuum test the crankcase so an air leak does not take the new piston.