Husqvarna FS 450 2019 Owner's Manual page 33

Perform major engine service including removing and installing engine. (Change
valves, valve springs, valve spring seats, and valve spring retainers. Change the
connecting rod, conrod bearing and crank pin. Check the transmission and shift
mechanism. Check the oil pressure control valve. Change the suction pump. Check
the force pump and lubrication system. Change the timing chain. Change all engine
bearings. Change the shaft seal rings and bearing seals of the main bearing.)
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One-time interval
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Periodic interval
Once after 10 operating hours
https://www.motorcycle-manual.com/
SERVICE SCHEDULE 9
Every 100 operating hours
Every 50 operating hours
Once after 20 operating hours
Annually
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