Rush SR Service Manual
  • Getting Started
    • Rush SR Specs
      • Why the GSXS-1000?
      • Dyno Sheet
    • Before Starting - Warnings
    • Removing Bodywork
    • Break-in and Initial Setup
      • Seat Mounting
      • Pedal Box Placement
      • Bedding Brakes
      • Engine Break-in
      • Driving and Shifting
    • Understanding Your Dash
  • Maintenance
    • Maintenance Schedule
      • Each Session
        • Torquing Wheels
        • Lubing Chain
      • Each Weekend
        • Checking Fuel Pressure
        • Clean & Adjusting Chain
        • Inspecting Nuts & Bolts
        • Checking Shock Pressure
        • Adjusting Throttle & Clutch Cable
      • Each Month/Quarter
        • Greasing Joints and Bearings
        • Changing Diff & Engine Oil
        • Inspecting & Bleeding Brakes
      • Each Year
        • Change Air Filter
        • Changing Coolant
        • Cleaning Fuel Filter
        • Inspecting Wheel Bearings
        • Rebuilding Shocks (Track Variable)
        • Cleaning Radiator
        • Replacing Chain (Track Variable)
        • Rebuilding Axles
      • Long-Term Maintenance (150hr+)
    • Fluids
    • Shock Diagrams
    • Torque Specs
    • Suzuki Service Manuals
    • Electronics and Wiring
      • Main Harness
      • Shift Harness
      • Dash Harness
    • Winterizing
    • Dash Alarms
    • Engine and Gearbox
  • Tunables
    • Factory Baseline Setup Guide
    • Anti-Roll Bars
    • Shock Adjustments
    • Gear Ratios / Sprocket Changes
    • Alignment and Ride Height
    • Diff Plate Stacks
    • Ballast
    • Chain Guards and Replacement
    • Left Foot Braking
    • Brake Pads and Rotors
    • Tires
    • Mirrors
  • Dash, Data, and SmartyCam
  • Wrapping Your Rush SR
  • Running & Consumables Costs
    • Comparison to Other Cars
  • Parts & Repair Costs
  • Transporting Your Rush SR
  • Competing in Events
    • Decals and Brand Assets
    • Technical Regulations
  • Getting Help
    • Rush SR Owners' Forum
    • Rush SR Facebook Community
  • Service Bulletins
    • 2023-05-19 Pedal Box Safety Notice
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  • Differences between Gen 1 and Gen 2 shift harnesses
  • GCU Pinout

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  1. Maintenance
  2. Electronics and Wiring

Shift Harness

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Last updated 24 days ago

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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:

PIN_UP

18

INPUT

PULLUP

Upshift paddle switch

Input through pin 10, filtered

PIN_DOWN

19

INPUT

PULLUP

Downshift paddle switch

Input through pin 9, filtered

PIN_NT

3 or 20*

INPUT

PULLUP

Neutral paddle switch

Pin 3 on KLine cars, 20 on DBW

PIN_TANK_PRESSURE

A6

INPUT

PULLUP

Tank air pressure sensor (analog)

Default 70-90psi hysteresis.

PIN_UPSHIFT_VALVE

4

OUTPUT

None

Air valve 1: upshift

PIN_DOWNSHIFT_VALVE

5

OUTPUT

None

Air valve 2: downshift

PIN_BLIP_VALVE

6

OUTPUT

None

Air valve 3: blip (KLine only)

KLine Only

PIN_IGNITION_INTERRUPT

7

OUTPUT

None

Solid-state ignition coil interrupt

KLine Only

PIN_COMPRESSOR_RELAY

11

OUTPUT

None

Compressor relay

PIN_GEARSHIFT_SENSOR

12

OUTPUT

None

Gearshift sensor mimic (PWM)

DBW Only

PIN_LR

53

OUTPUT

None

Debug LED (red, blip)

Debug LED

PIN_LY

47

OUTPUT

None

Debug LED (yellow, downshift)

Debug LED

PIN_LG

41

OUTPUT

None

Debug LED (green, upshift)

Debug LED

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.

42KB
51700 RevB.pdf
pdf
Shift harness diagram for mechanical throttle car