Shift Harness
The shift harness collects signals from the steering wheel and operates the pneumatic sytem to shift the car.
The shift system is powered by a connection to the main harness, which has two fused circuits in it. The signal fuse circuit powers the control units in the shift system and the compressor (ABS) fuse circuit powers the compressor.
The signal fuse circuit is turned on via the ignition switch in the car. It supplies power and ground to the shift harness via pin 1 and 2, respectively, of the main harness connector.
The compressor fuse circuit is directly connected to the battery, and under normal circumstances always supplies power to the shift harness via pin 5 of the main harness connector. The compressor is switched on or off by the gear control unit (GCU) and relay in the shift harness. The compressor fuse circuit repurposes one of the ABS circuits from the bike, and is labeled such in the fuse box.
The steering wheel coil cable connection carries the signals for the up, down, and neutral commands on the blue, green and pink wires (todo: look up specifics). The black wire in pin 1 is the common wire for the shifting signals. Pins 3 and 4 of the steering wheel coil cable connector connect to the push to talk button on the steering wheel. These black and white wires are left unconnected in the shift harness for use with external radios or other devices. They extend approximately 12" in the shift harness and can be found in the loom near the bend around the top frame tube.
Differences between Gen 1 and Gen 2 shift harnesses
Gen 1 shift harnesses and GCU's are used with mechanical throttle body cars. Gen 2 shift harnesses and GCU's are used with the drive by wire throttle body cars. The easiest way to tell which generation engine is in a car is to check the pedal box for a throttle cable or accelerator pedal sensor.
The gen 1 shift harness is shown above. The tan and white wires running between the main harness connector and the GCU 4 pin connector are specific to the gen 1 harnesses. They carry the ignition coil power to provide ignition interrupt.
The gen 2 shift harness has some changes required for the drive by wire throttle. The white and tan wires are no longer used. They are replaced by a green wire which goes from pin 4 of the main harness connector to the GCU 19 pin connector. The new green wire carries the signal to the ECU for shift assist. The wires E and F in the valve block connector as also unused.
GCU Pinout
Detailed Pin Table
For debugging purposes, we provide the following pin table for the GCU:
Input Pins
Upshift paddle switch
18
Filtered through pin 10.
Downshift paddle switch
19
Filtered through pin 9.
Neutral paddle switch
3 or 20*
Pin 20 on KLine cars, 3 on DBW. Filtered through pin 8.
Tank air pressure sensor (analog)
A6
Default 70-90psi hysteresis.
Explanation
Inputs with Pullups: The paddle switches (PIN_UP, PIN_DOWN, PIN_NT) are all set as INPUT_PULLUP, meaning they use an internal pull-up resistor. Switches connect to ground when pressed.
Filtered inputs for up/downshift paddles reach the intermediate board on pin 9/10, are filtered through a capacitor, then reach the logic board at pin 19/18. Jumping 9 to 19 or 10 to 18 will skip this filter.
Analog Input: The tank pressure sensor uses analog pin A6 and is set as INPUT_PULLUP. It is a 10-bit sensor and reads 0.1633psi per unit.
Output Pins
Air valve 1: upshift
4
Triggers air shifter
Air valve 2: downshift
5
Triggers air shifter
Air valve 3: blip
6
KLine only; pulls throttle cable
Solid-state ignition coil interrupt
7
KLine only; interrupts ignition coils
Compressor relay
11
Turns on air compressor
Gearshift sensor mimic (PWM)
12
DBW only; emulates bike gear lever sensor to initiate blip/throttle cut
Debug LED (red, blip)
53
Debug LED
Debug LED (yellow, downshift)
47
Debug LED
Debug LED (green, upshift)
41
Debug LED
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