TUN
9-7
NOTE:
NOTE:
• When checking the discoloration of spark
plugs, be sure to stop the engine immediately
after a run and check.
• Avoid racing.
• When changing the heat range of spark
plugs, never attempt to change it more than
±1 rank.
• When using a spark plug other than standard,
check its heat range against the standard and
check that it is a resistance type.
• Note that even if the discoloration seems
proper, it may slightly vary with the spark plug
maker and oil in use.
CHASSIS
SELECTION OF THE SECONDARY
REDUCTION RATIO (SPROCKET)
<Requirement for selection of secondary gear
reduction ratio>
• It is generally said that the secondary gear
ratio should be reduced for a longer straight
portion of a speed course and should be
increased for a course with many corners.
Actually, however, as the speed depends
on the ground condition of the day of the
race, be sure to run through the circuit to
set the vehicle suitable for the entire
course.
Secondary
reduction ratio
=
Number of rear wheel sprocketteeth
Number of drive sprocket teeth
Standard secondary
reduction ratio
YZ85:
47 / 14 (3.357)
(for EUR, CAN)
48 / 14 (3.429)
(for AUS, NZL)
YZ85LW:
52 / 14 (3.714)
ENGINE / CHASSIS
