Zipper Mowers Thunder-Max 309-365 User Manual
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Step 2d
Insert AutoTune power/communication 4-pin
plug into the bike’s data port (gray), located at the base
of the battery, left side of the bike.
Step 2e
Remove the factory oxygen sensors and install
the wide-band units in their place.
Step 2f
Front sensor: route wiring along frame rail
(double up harness if necessary), position harness plug
at lower front primary cover area. Connect the sensor to
the closed loop module, secure with wire ties.
Step 2g
Rear sensor: Route wiring down the left frame
rail behind the primary housing, with the plug located
along the frame turn. Double-back the wiring to the rear
sensor. Connect the sensor to the closed loop module,
secure with wire ties.
Oxygen Sensor Installation Notes
The wide band sensors are longer than the factory
sensors. Installation of the wide band sensors into
factory headpipes presents no clearance problems,
however, some aftermarket pipes may require exhaust
pipe modification or sensor bung relocation for
interference-free installation. The sensors must mount
freely without contacting surrounding components. If
this is not possible, do not attempt to bend or
modify the sensor in any way as it is a sensitive
electronic component and will be damaged if you do.
Modify the pipe if required for clearance. Weld-in bungs
are available for exhausts systems not equipped with
bungs or if current bungs present clearance issues.
Bungs should be located no more than 3-4” from the
head/pipe connection (for ideal location, refer to the
factory location on 2007-up models). Weld-in bungs are
available from Zipper’s (#272-200, straight; #272-202,
angled). Chase the threads after welding with an 18 x
1.5mm tap (available from auto parts stores) and verify
that the oxygen sensor threads in easily without the pipe
wall interfering with the sensor tip. After installation,
route the sensor harness away from the engine and
along the frame when possible, above the lowest frame
point to avoid the possibility of dragging ground during
operation. Avoid routing harnesses where engine
movement or moving parts can contact and damage the
harnesses or connector plugs.
The AutoTune harness for the rear cylinder sensor is
shorter and can be easily identified by black tracers on
all of its wires; both plugs are clearly marked for front
and rear use. It is very important to install these
correctly or the engine will perform poorly! Tie the
harnesses to the frame or existing component
harnesses, taking care to avoid contact with any
vibrating component that may chaff the sheathing or
wires. Some disassembly of bike components may be
required for best harness routing.
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309-365 Installation / Setup Guide V2009.04.23
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