bike dies when releasing the clutch

[pcz87ninja]

I have a 1987 750 ninja that dies when I release the clutch, starts fine, idles fine in neutral and when clutch is pulled in, any gear when releasing the clutch it dies. I checked the kick stand button it is not stuck, was recomended to try bypassin the switch by cutting the 2 wires and connecting them together,still does not work, seperated the wires , still nothing ,, Dont know what else to look for , would appreciate any help,,,Thank You

[hayward6]

does it just cut right out as if you turned it off or is there some hesitation first? I'm trying to make sure there isn't some type of drive train issue, if you roll it and drop the clutch does the engine turn over or just lock the rear wheel?

If it's just cutting out clean, you must have a sensor or wire thats bad somewhere.

[pcz87ninja]

it does cut right out like i turned it off, was kinda worried it could be internal, but it first did this Friday night, pulled it back in the garage, pulled the filler cap off the clutch, was a little low on fluid , filled it, messed with the kick stand , kicking it back and forth a few times, then took it out started it, and it actually took off and i road it a couple miles and come home and parked it , next day went to ride and it is doin the same thing, so i dont think its in the drive train (fingers crossed). I did disconnect the kick stand switch, was wondering maybe if there was some kind of other switch or sensor that i should check, thank you for your help.

[hayward6]

yeah if it's intermittent your probably looking at a faulty switch or wiring. Heres a few of the things I know to check...

clutch switch connection, make sure its clean and seated fully.
stand switches, both side stand and center stand if its got a switch there.

I'm of the opinion that its got to do with the side stand switch... are you sure wiring the two ends together is how its bypassed? and have you checked the other end of those wires? maybe its as simple as a fuse or bad wiring further into the bike.

[StarGate]

+1 on the most likely cause being sidestand switch. Does it die as soon as you let the clutch out if it's in neutral? If it doesn't then that just makes it sound even more like the stand switch. But like Hayward, I'm not sure if thats a normally open or normally closed circuit. If you have the schematic you might follow those wires from the sidestand up to make sure there isn't a problem in that circuit thats farther down the line.

[RichLockyer]

Sidestand switch is ignored in neutral... should run all day with the stand down and clutch out in neutral.

Sounds like simultaneous failure of BOTH the sidestand switch and neutral switch. The clutch switch is obviously working, because releasing it kills the engine.

Does the neutral light come on when in neutral?

[pcz87ninja]

hayward, not sure if connecting those 2 wires bypasses the switch, was just recommended by someone on here to try it cause it worked for theyre bike which is a BUELL , he said it may or may not work, and yes the neutral light does come on in neutral, goin to try to run those wires down and make sure the center stand does not have a switch which Im almost certain it doesnt, also will check for any fuse,thanx guys for all your help, ill check these things you all suggest it might be, i know this really is beginning to suck , driving me crazy knowing its prob. something simple, thanx again guys, will post back tonite. P.S. RichLockyer, how do you know or check to see if the neutral switch is bad, I do remember my neutral light coming on a couple times riding and it wasnt in neutral ?

[hayward6]

Originally Posted by pcz87ninja

I do remember my neutral light coming on a couple times riding and it wasn't in neutral ?

Thats a good sign that it's bad or theres a loose wire

[adtremzx10r]

I have a feeling your on the rite track with it being the side stand switch. The wires need to be connected to complete the circuit. Make sure you are connecting the wires to the main harness and not to the kickstand switch.

[Ericthejet]

Will the bike start in neutral with the sidestand up?

This may help. It's for the 84 to 92 Kawasaki Gpz 900. Most of the issues could be the same.
************************************************** ************************************************** ********************************

GPZ 900R 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 900R'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 900R'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.

[adtremzx10r]

holy cow thats a long answer. I have to say after reading that I have no idea what it has to do with this guys problem. Thats alot of words saying nothing at all except that you know theroy principals of motorcycle safety switches.
P.S. the relays are not servicable there are in a component called a junction box. and needs to be replaced as a unit if needed. Assume = ***-U-Me

[RichLockyer]

Originally Posted by adtremzx10r

Thats alot of words saying nothing at all except that you know theroy principals of motorcycle safety switches.

#1 - It was a cut and paste from the shop manual
#2 - It DOES provide information pertinent to troubleshooting the OP's problem. It's a bit wordy, but it is complete.