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2. Protecting the drivetrain from sudden impact or shock loads (such as
landing from a jump with the engine at full throttle).
From the factory the slipper clutch is set for minimal slippage, just
enough to protect the drivetrain from shock loads. On slippery, low
traction surfaces such as a hard-packed, dry racetrack you may benefit
from loosening the slipper adjustment nut to allow for more clutch
slippage. This will make the truck easier and more forgiving to drive
by helping to reduce the amount of wheel spin. Loosening the slipper
adjustment can also improve performance on extreme high traction
surfaces by preventing the front end from lifting off of the ground
when accelerating. Make slipper adjustments in small
1/8 turn increments.
The maximum tight setting for the slipper is just at the point where
there is little or no tire slippage on a high traction surface such as
carpet or a prepared racetrack. The slipper should not be tightened to
the point that clutch slippage is completely eliminated. Do not over
tighten the slipper nut or you could damage the slipper bearings,
pressure plates, or other components.
Adjusting the Two-Speed Transmission
Jato comes equipped with an adjustable two-speed transmission. When
the shift point on the transmission is adjusted correctly, it will maximize
acceleration and improve drivability. Use a 2mm hex wrench to adjust the
shift point. To make the adjustment, the engine must be off (not running).
1. Remove the rubber access plug from
the top of the transmission housing.
2. While looking through the opening, rotate
the spur gear to align the cutout (notch)
on the internal 2-speed clutch drum with
the opening.
3. Hold the spur gear and slowly roll the
truck forward until the hex on the black
adjustment set screw becomes visible in
the opening. Note: The two speed will
only rotate inside the drum when the
truck is rolled forward. The truck can be
rolled forward and back until the set screw
becomes visible.
4. Insert the 2.0mm hex wrench
through the clutch drum and into
the adjustment screw.
BASIC TUNING ADJUSTMENTS
5. Turn the adjustment screw 1/8 turn
clockwise to raise the shift point (shifts
later). Turn the adjustment screw counter-
clockwise to make Jato shift sooner. Be
careful not to loosen the adjustment
screw too much or you may cause the
screw and spring to fall out (requiring
major disassembly and repair).
6. Reinstall the rubber access plug to prevent
dirt from entering the transmission. Do not put oil or other lubricants
into the transmission through the two-speed adjustment access.
7. Check performance by running a test lap after each adjustment. On a
small race track with many tight turns, try setting the shift point later
so the truck only shifts into second gear on the main straightaway.
This will prevent an unexpected shift in the middle of a turn. On larger
tracks it may be necessary to allow earlier shifts for increased speed.
Adjusting the Spur Gear/Clutch Bell Gear Mesh
The ideal spur gear/clutch bell gear mesh for Jato
is 0.1mm. To set the gear mesh, place a strip of
standard letter/A4 size copy or printer paper (about
0.1mm thick) between the mating teeth. Loosen
the four engine mount screws from the bottom
side of the chassis (see image) and slide the engine
mount up to push the clutch bell gear against
the spur gear so the paper is not too tight to pull
out or too loose that it will fall out. Tighten the
engine mount screws securely. When the paper is
removed, you should feel only the slightest amount
of play between the gears (almost none) and there
should be no binding or friction.
Changing the Spur Gear
Remove the three screws on the slipper clutch
assembly using a 2.5mm hex wrench. Slide the
spur gear off of the slipper shaft. If the spur gear
is too tight on the shaft, gently pry on the back
of the gear with a flat screw driver to loosen it.
Repeat the steps in reverse order to install the new
spur gear. If the new spur gear is a different size,
then the engine mount screws will need to be loosened to readjust the
gear mesh (see above).
Shift
Later
JATO 3.3 • 33
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