Polaris 120 XC SP Youth Universal Owner's Safety And Maintenance Manual page 75

MAINTENANCE
NOTE: Measure at the point where the weight is hanging.
4. Check for specified slack between the wear surface of the track clip
and the plastic hi-fax (C).
If the track needs adjustment:
5. Loosen rear idler shaft bolt (D).
6. Tighten or loosen the track adjusting screws (B) as necessary to
provide equal adjustment on both sides of the track.
7. Repeat measurement on the other side of the track. NOTE: Check
more frequently when machine is new.
8. Start machine and slowly rotate the track at least five revolutions,
let the track stop rotating by itself (do not apply brakes).
9. Check track alignment (side to side) by comparing the distance
from the guide clip to Hi-fax on both sides. Readjust until
centered.
10. Tighten Idler Shaft Bolt (D)
11. Readjust the toe block to proper spacing and tighten.
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