The Ignition circuit on the 600r is fairly straightforward, complexity not being an issue. The difficulty with this circuit lies in it's integration with the starter circuit - many possible earth paths and power supplies are common to both circuits; therefore we must use caution when trying to identify the cause of any given problem. Hopefully the following text will not only explain how the ignition circuit functions, but how the starter and the ignition circuits are linked.

As previously discussed in the article on the starter circuit, Kawasaki have a "safety first" philosophy on the 600R - starting the machine in gear was recognised as a real hazard and so was riding off with the sidestand down!

To prevent the machine being started in gear, Kawasaki designed the starter circuit in a manner, which disabled the start system, if several mechanical conditions were not met. Similarly, the ignition circuit was designed to facilitate disabling the ignition should the rider attempt to pull away with the side stand in the down position.

With the Sidestand down, and no other earth is available to the Ignitor unit, power is supplied to the warning light on the instrument console. If the Sidestand is up, the warning light is extinguished and an earth is provided to the Ignitor unit.
The Purpose of the Ignitor Unit

The Purpose of the Ignitor Unit. (CDI unit)

The four main functions of this unit are;

1. The provision or cessation of ignition dependent upon the status of various switches and earth paths on the machine.
2. To receive engine speed and timing signals from the pick up coils.
3. To advance or retard ignition timing according to engine speed.
4. To compute and schedule an accurate timing signal to the ignition coils.

Although these units are usually reliable, they have been known to croak now and then. Having said that, it is often the case to some degree that a problem thought to be originating from the ignitor is, in fact, merely an unreliable signal going into the unit - remember the old saying "garbage in, garbage out" - the Ignitor unit is a computer and will act as such, so care must be taken when troubleshooting.

The benefits of the IC Ignitor system are many fold, the unit is light, small, and like the coils, there are no moving parts - thus reliability is virtually assured .

At Diagram 2, is a much schematic drawing of the ignition system showing relays inside the Ignitor unit. I must stress that this is drawn for clarity and understanding only - the actual unit is solid state with no moving parts whatsoever.
The reason for depicting the internals of the unit in this manner, is to clearly provide an understanding of the various inputs and outputs common to this unit, and how they interact together.

Let us now describe the sequence of events that occurs within the unit, using diagram 2 as our reference.

When the ignition is set to on, power is supplied to the ignition coils and the IC Ignitor unit.

The starter button is depressed and if an earth is available from the neutral switch, or the starter lockout switch, then, and only then will the starter circuit relay energise. This in turn allows the starter solenoid to energise, and we then have battery power to the starter motor and engine rotation begins.

This is a where the starter system hands over to the ignition system, because it is with engine rotation that the CDI unit starts to fuction.

Whilst the crankshaft is turning, a magnet on the end of the crank (termed the "rotor") passes two pick-up coils, 180 degrees apart. A small amount of current is induced into these coils as the magnet passes, and this momentarily energises “relay” A or B.

“Relay” C is energised when an earth is available from the neutral switch, the starter lockout switch or the sidestand switch. With this relay closed, the momentary closure of relay A or B will result in an earth being available to the ignition coils and current flow is established through the coils, resulting in a high voltage delivery to the spark plugs.

Ignition circuit -V- starter circuit

The Sidestand switch has no role to play in the Starter circuit whatsover. It’s primary function is to provide an earth to the IC Igniter unit whilst the motor cycle is in gear, and being ridden. This is the only earth that the Igniter unit can utilise whilst the machine is in gear. Without it, the igniter unit cannot function.

Thus, if you're riding along and the engine suddenly dies, suspect this sidestand switch as the culprit. If the engine starts but will not pull away, this is almost definitely the culprit. As an emergency repair, you can join the Brown/Red wire to the Black/Yellow wire at the side stand switch connection. I carry a scotchlok connector in case I need to do this at the roadside.

Subsequent to any troubleshooting you may carry out to determine the cause of a problem, try a variety of functional checks that may help isolate the components in that circuit as being serviceable or defective. Both of these circuits not only share the same 30 Amp fuse, but the majority of the earths too. It is finding the components that function correctly that narrows the field in where the defect lies.

The IC Ignitor unit itself can be checked with a decent multimeter, full instructions on this check can be found in the Kawasaki manual, although this should be low priority on your checklist - as I stated earlier, these units rarely fail.

Always start troubleshooting with an open mind and be realistic; look at components or wiring that is susceptible to weather, vibration or wear. A moving part is much more likely to fail than its stationary counterpart - such as a relay to an SCR (Thyristor) or a switched earth to a fixed earth. Use logic and refer to the old saying, If stuck call Craig !

Summary - The birth of a spark.

Switch the ignition on and the set the engine kill to run. If this is not switched to RUN, current is not supplied to the Igniter (CDI) unit, or the starter circuit, and the starter will not turn.

Current is now supplied to the Igniter (CDI) unit, and seeks an earth via either:-

A: neutral switch. (Must be in neutral (Green indicator light))

B:- starter lock-out switch (Clutch lever must be in, indicating that although the machine is in gear, the rider has control of it)

The starter circuit relay is energised, which then, and only then, allows the starter solenoid to operate, and supply power directly from the battery to the starter motor.

It is with engine rotation that the IC igniter (CDI) unit starts to do it's stuff.

As the engine rotates, and the magnetic rotor mounted on the end of the crankshaft passes each pulser coil. It induces a small current in each of these pulser coils. This current heads towards the ignition coils via the CDI unit which uses the current to provide a "momentary" earth for each of the ignition coils.

As this current flows through the ignition coil, a magnetic field is induced within the coil' for the period that the crankshaft mounted rotor is passing the pulser coil (pickup triggers). Once the rotor has passed the pulser coil, the "momentary" earth that it has been providing for the ignition coil is removed.

When this momentary earth is removed, the magnetic field that has built up in the coil collapses. As it collapses, it induces a high voltage which is delivered to the spark plug via the HT leads, it jumps the electrode gap of the spark plug in search of an earth which it finds via the engine block.

We have igniton ! Now get out there and enjoy it !

GPZ 600R ELECTRICAL STARTER CIRCUIT Introduction It is important to understand that the Kawasaki engineers developed this circuit with safety being a primary objective. The main philosophy centres around the danger that arises when the starter motor is energised with the bike in gear and the clutch engaged. As this was a common occurrence on other earlier motorcycles and recognised as a real hazard, Kawasaki decided to design a circuit that was foolproof - in other words, the inadvertent starting of the engine whilst in gear was simply not possible. The logic behind this system is very straight forward, - so long as the "drive" is engaged you cannot start the engine. This essentially means that the engine can be started with the bike in gear, as long as the clutch is disengaged, (lever in) or, the engine can be started with the bike in Neutral, whereby the clutch status is irrelevant. Simple ! But please note that sidestand position is NOT a factor in this circuit. System Description and Operation
The circuit consists of two Relays, the Starter circuit Relay and the Starter Relay. Two Switches are employed, namely the Starter Lockout Switch and the Neutral Switch. The Starter Circuit relay is Located in the junction box and is the lower of the two circular relays. ( Most of the workshop manuals refer to 3 x relays, however most GPZ 600R's only employ 2.) The Starter Relay is located just forward of the junction box and is the lower of the two rubber sleeved relays. The Starter Lockout Switch lives underneath the Clutch lever assembly, and the Neutral switch sits adjacent to the oil level sight glass. In order for the Starter Circuit Relay to operate, it relies upon an earth signal being provided by either the Starter Lockout Switch, or the Neutral switch. The starter Lockout switch, is located on the clutch lever assembly, and, when the clutch lever is pulled in, an earth is provided from the main electrical system ground. With the Clutch lever out, the earth is obtained through the Neutral switch (providing of course that the gearbox is in Neutral). Suffice to say, that if the clutch lever is out, and the bike is in gear, pushing the starter button will have no effect! What should happen! With the ignition on, and the Starter button depressed, power is supplied to the Starter Circuit Relay from the battery, and, provided that the Starter Circuit Relay is supplied with an earth signal, it will then provide power to energise the coil in the Starter relay which has a fixed earth. The contacts in the Starter Relay will then close, and Battery power is routed to the starter motor. Troubleshooting the system Okay, so the Ignition is on, you've pressed the starter button and nothing happens. Let's do all the basic checks first: Is the engine kill switch set to run? Is the Green Neutral light illuminated? Does the battery have plenty of Volts? Let's assume that you answer "Yes" to all of the above. Use the trouble shooting guide below, but bear in mind, that this guide is designed to prove the starter circuit's components, and as with all things electrical, chafed wires, poor earth's and cunning wiggly's may feature in any problem you may experience. Electrical problems are often very difficult to locate and solve.
To Prove the Starter Circuit Relay This is easy, remove the Main relay, (which is above and to the right of the starter circuit relay) and swap them over. These relays are identical, and can be interchanged. The bike will start and run without the main relay, but you'll have no electrics. ( Nb :- Many of the workshop manuals show 3 x relays, whereas the majority of GPZ 600R's only utilise 2) To Prove the Starter Relay Again, relatively simple to prove. Turn the ignition on. Disconnect the small plug on top of the starter relay, and, with the starter button pressed, check for a 12V supply between the Red/Yellow wire (+'ve) and the Black/Yellow wire (-'ve). Refit the connector. Press the Starter Button once again, and this time check for a 12V supply on the "Out." terminal of the relay. Ie, the wire that feeds down to the starter motor, this is on top of the relay, on the left, and has a rubber cap on the terminal. To Prove the Neutral Switch Simplest of them all, it does most of it itself! With the machine in Neutral, and the ignition switched on, is the Green Neutral light illuminated on the instrument cluster? If it is, then the Neutral indicator switch is working. If it's not the bike may be in gear, the bulb blown, or the switch faulty. If the Neutral switch appears to be faulty, disconnect the light Green wire from it, connect the wire to an earth, and attempt to start the machine, if it starts, the neutral switch is faulty. To prove the Starter Lockout Switch Assuming that the two relays are serviceable, and that the neutral switch is serviceable. Turn the ignition on, pull the clutch lever in and press the start button. If the machine fails to start, the starter lockout switch must be considered to be at fault, or another fault exists elsewhere within the circuit.