RIEJU marathon 125 Owner's Manual page 106

TRANSMISSION CHAIN ADJUSTING AND LUBRICATION
To correct the chain tension, loosen the rear axel
bolts and turn the adjustment plates of the rear
wheel axle clockwise to tighten the chain and
anti-clockwise to loosen the chain. Turn the rear
Chain tensioner
wheel several times and check the tension in
various areas to find the point at which the
chain is at its tightest point.
To check the chain adjustment the chain tensio-
ner must be pulled away from the chain. The
chain should have 35 – 45 mm of movement.
Chain tolerance 35-45 mm.
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