32 • SLAYER PRO 4X4
Adjusting the Two-Speed Transmission
Slayer Pro 4x4 comes equipped with an adjustable two-speed
transmission. When the shift point on the transmission is adjusted
correctly, it will maximize acceleration and improve driveability. Use a
2mm hex wrench to adjust the shift point. To make the adjustment, the
engine must be off (not running).
1. Shift the transmission into forward
gear (shift button down).
2. Remove the rubber access plug from
the top of the transmission housing.
3. While looking through the opening,
rotate the spur gear to align the
cutout (notch) on the internal two-
speed clutch drum with the opening.
4. 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 truck
will only roll forward (not backwards)
when the spur gear is held stationary.
5. Insert the 2.0mm hex wrench
through the clutch drum and into
the adjustment screw.
6. Turn the adjustment screw 1/8-turn
counterclockwise to lower the shift
point (shifts 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). Turn the adjustment screw
clockwise for later shifts.
7. 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.
8. 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 that 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 Slayer Pro 4x4 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 two horizontal engine mount
screws and slide the engine mount up
to push the clutch bell gear against the
spur gear so that the that the paper is not
too tight to pull out or too loose that it
will fall out. Tighten the two horizontal
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
1. Remove the four cap head screws that
secure the engine to the engine mount.
2. Remove the button head screw that
secures the pipe hanger to the rear
body mount.
3. Carefully remove the engine and exhaust
system from the spur gear area to allow
enough room to remove the spur gear.
4. 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 above steps in reverse order to install the new spur gear.
BASIC TUNING ADJUSTMENTS
Shift
Sooner
