Wiring Diagram

Below is explained how to connect the wiring to let just the engine run. This part is also the first step if you need to rewire the bike completely or to check the wiring for errors (if the engine will not run). When you look at the original wiring diagram (click on the links below to view or download (to download, right click, save target as...) the wiring diagrams), it is kinda hard to read and diifcult to find out what causes a problem. Therefore I created a simple version of it. When rebuilding the wiring, next thing to do is to build up the rest (lights and signals).

If you have any comments or improvements, let me know.

RD400 Wiring Diagrams in .PDF

RD400C/D
RD400E
RD400C/D/E USA
RD400F Daytona

Below the wiring diagram that will be explained.

Figure 1: Wiring Diagram

Behind the sidecover (where also the fusebox is placed) are three connectors to connect the rectifier, regulator and the fusebox. The connectors in figures 3, 4 and 5 shows what wires (color) according to the original wiring diagram of the RD400C, are normally connected to this connectors, looking from above (like in figure 2). Okay, here we go!

Figure 2: Groundplate

Connect a red wire from the + pole of the battery to the red connection on the fuse connector (figure 5). It doesn't matter if you connect it on the left or right aslong you will be consistent.The connections (both sides) from the fuse connector are going directly to the fuses (for example we'll use the left connector).


Figure 3: Regulator connector (top)

Connect with a red wire the right connection (red connection) of the fuse connector with the red connection of the rectifier (figure 4), also loop this one to the mainswitch (red connection).


Figure 4: Rectifier connector (right)

From the mainswitch (the mainswitch at position 1, so that there is a connection with the red wire from the fuse connector) connect a brown wire back to the fuse connector at the left brown connection (figure 5).

Figure 5: Fuse connector (left)

Connect from the right connection on the fuse connector (brown) a brown wire to the killswitch (figure 6). According to the original wire diagram the color of the wire of the killswitch is brown, but it can be green/black, so measure the killswitch for the right connections.


Figure 6: Kill Switch

Connect a wire (this should be a red/white wire, but those are difficult to get) from the killswitch (the other wire) to the resistor that is placed below the fueltank at the front of the frame (figure 7). Connect the wire to the white/red connection (figure 7).


Figure 7: Resistor

Connect 2 wires (red/white connections) from the resistor to the ignition coils (red/white). Use the left connection of the resistor for the left ignition coil and the right connection for the right ignition coil (figure 8). The ignition coils are placed below the fueltank.


Figure 8: Ignition Coil

There are 2 connections at each ignition coil. One connection is for the power supply (red/white connection) and one is coming from the ignition (grey or orange wire).

Connect a grey and orange wire (for each ignition coil one wire) from the ignition coils to the ignition and must be connected at the orange and grey wires coming from the capacitors on the ignition (figure 9).


Figure 9: Ignition Connector

At the ignition connectors there is a connector with 3 white wires. These white wires must be connected to the white connections of the rectifier (figure 4).

There is also coming a green and brown wire from the ignition (figure 9). These wires must be connected to the green and brown connections of the regulator (figure 3). The black connection (from the ignition) must be grounded. This applies also to the - pole of the battery, the black connection of the regulator and the black connection of the rectifier. The main ground connection to the frame is at the bottom at one of the ignition coils (where you tighten the
coil to the frame). Create a ground connection here and connect all black wires to this point, so that the frame of the bike is used as ground.

Well that should be it. Put the mainswitch to position 1 and start the bike!