- Removes excess slack in the timing chain to prevent damage to the pistons and valves
Husqvarna -- FC 350 -- (2019, 2015, 2018, 2020, 2014, 2016, 2017); Husqvarna -- FE 450 -- (2019, 2016, 2018, 2017); Husqvarna -- FE 501 -- (2015, 2017, 2020, 2016, 2019, 2014, 2018); Husqvarna -- FE 250 -- (2017, 2019, 2016, 2018, 2015, 2014); Husqvarna -- FE 350 -- (2016, 2015, 2020, 2014, 2017, 2019, 2018); Husqvarna -- FS 450 -- (2020, 2018, 2017, 2019); Husqvarna -- FC 250 -- (2016, 2017, 2018, 2020, 2015, 2014, 2019); Husqvarna -- FC 450 -- (2015, 2017, 2018, 2016, 2020, 2019, 2014)