Yamaha XZ550RJ 1982 Service Manual page 146

COOLING SYSTEM
The coolant is circulated by an impeller-type pump
mounted on the right-hand crankcase and driven by
a gear. The coolant is drawn by the pump from the
bottom tank of the radiator, through the outlet pipe,
and discharged into the cylinder and cylinder head
through the joint pipe. The coolant passes from the
cylinder to the cylinder head
through coolantways, and after circulating around
combustion chamber jacketing, enters the radiator
upper tank via the inlet pipe. The heated coolant
from the engine then passes down through the
finned tubes to the bottom tank of the radiator.
These finned tubes present a large surface area to
the air and dissipate the heat.
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