Husqvarna TC 250 2010 Workshop Manual page 209

ENGINE REASSEMBLY
Refit the four shim (5) on the valves and the valve buckets (6) as marked on
removal.
Check the bearings of the timing drive upper gear (7) and replace them if
needed.
The gear (7) requires no timing.
Refit the gear (7) with its shaft (8) and gasket (9).
Tighten the screws (10) with a Phillips screwdriver (4 Nm, 0.4Kgm, 2.9 ft/lb,
Loctite 243).
Push the gear until exposing the groove and fit the retaining ring (11).
Part. N. 8000 H1489 (10-2009) H.47