Monday, May 4, 2009

The Wiring Harness

Full Loom, graphically segmented. (Full Size Here)
As previously mentioned, I received a near complete wiring harness along with the R1 engine. The primary items that are missing are the headlight / guage cluster wiring harness and the Sub harness that includes the spark plug connections (one of the sub harnesses, can't remember which number). I do have the sub harness that connects up with the Fuel Injection ports and some other sensors. Along with the MK Kit, I am also receiving a modified Harness to fit the chassis. After completing the exercise (described below) with wiring today, I'm sure I could've done without purchasing a new wiring harness, but it fit in my budget and I decided to go with it. Maybe the MK specific harness will also leave off any unnecessary connections and will save weight and prevent some amount of builder confusion.

So, the goal of today was to go through the entire harness and tag every connection. I was able to download the 2004-2006 Yamaha R1 Service, Owners and Parts Manuals which was a start. I found the full colored wiring harness diagram at the very end of the service manual. However, Yamaha's version is fairly confusing. To be safe, I also purchased Haynes Service Manual and recieved it a few days ago. For anyone who's not an expert on this engine and is currently or planning to build an R1 powered car, I highly suggest you get this manual. It details just about every DIY operation, from general inspection and maintenance to some heavy duty repair. A big benefit to this manual is their Wiring Diagram. It's much clearer than Yamaha's version and only contains one error (that I could see).

I started out by studying the wiring diagram for a bit and labeling up the smaller sub harness that I already had. This just got me in the mode of how to efficiently read the diagram. It soon became very easy to understand. Any simple connection usually ends at either a sensor, switch or light. The connections from the main harness that connect up with sub looms are easy to spot as they have multiple connections / wires and on the diagram, these are denoted by long white boxes / strips that are meant to mimick the connector block. If you've never read a wiring diagram, have no fear, haynes makes it simple.

Below I've zoomed in on the segments from the image at the top of this post. I've labeled everything with an arrow and number and have listed exactly what the connection goes to below the image. Hopefully this helps anyone who's trying to figure out their loom. (Be sure to reference the image at the top to help you get a bearing on where on the loom the image is taken.)

1.1) Fan Relay
1.2) FuseBox

2.1)Fan Motor (One of two, see box 6)
2.2)Main Ignition Switch (Wires to Power & Fuse)
2.3)Main Ignition Switch (Wires to Fuse)
2.4)Connections to: Clutch Switch, turn signal switch, dimmer switch, horn switch
2.5)EXUP Servo

Box 3 (Full Size Here)

3.1) EXUP Servo
3.2) Coolant Temperature Sensor
3.3) Primary Throttle Position Sensor
3.4) Servo
3.5) Secondary Throttle Position Sensor
3.6) Intake Air Pressure Sensor
3.7) Intake Air Temperature Sensor
3.8) Fuel Injection 1
3.9) Fuel Injection 2
3.10) Fuel Injection 3
3.11) Fuel Injection 4
3.12) Connection to Main Harness

4.1) SideStand Switch
4.2) Oil Level Sensor
4.3) To: Regulator / Rectifier
4.4) Fuel Level Sensor
4.5) Fuel Pump
4.6) Crankshaft Position Sensor
4.7) Rear Brake Light Switch
4.8) Speed Sensor
4.9) Neutral Switch
4.10) Grounding Wire

5.1) Tip Over Sensor
5.2) Atmospheric Pressure Sensor
5.3) To: Rear Turn Signals & License Plate Light
5.4) Brake / Tail Light
5.5) Relay Assembly
5.6) Turn Signal Relay
5.7) Starter Relay (Connection to starter is not shown, but sits next to battery terminal)
5.8) To Battery
5.9) 50 Amp Fuse

6.1) To: Front Brake Light Switch, Engine Start Switch, Engine Stop Switch
6.2) Fan Motor
6.3) To: Camshaft Position Sensor, Ignition Coils / Spark Plugs, AIS Air Cutoff Valve
6.4) To: Headlight Harness
6.5) To: Guage Cluster
6.6) ECU

2004-2006 R1 Wiring Diagram (Full Size Here)


  1. You are amazing my friend. This is going to be very handy! Thank You!

  2. 6.4 and 6.5 is the other way round....

  3. to which we are connecting to scaning the ecu?


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