A 45mm piston kit for the Husqvarna 51 and 50 Special chainsaws. It replaces 503167701. Some 50s were built at 44mm, so measure the bore or the old piston before ordering. A scored piston is usually a lean condition, so pressure and vacuum test the crankcase and fix any air leak or fuel fault before the new piston goes in. Check the cylinder for scoring and aluminum transfer, use a ring compressor, fit the circlips fully and check the carburetor tune.
- 45MM PISTON KIT - Piston, rings, wrist pin and circlips.
- FITS HUSQVARNA 51 AND 50 SPECIAL - The 45mm saws. Some 50s were built at 44mm, so measure the bore or the old piston before ordering.
- REPLACES 503167701 - If your parts list shows that number for the piston, this kit covers it.
- FIND THE CAUSE FIRST - A scored piston is usually a lean condition: an air leak at the intake or crank seals, or a fuel fault. Pressure and vacuum test the crankcase before the new piston goes in.
- INSTALLATION - Check the cylinder for scoring and aluminum transfer, use a ring compressor, fit the circlips fully with the gaps away from the notch, and check the carburetor tune before working it hard.