TOPIC:

Can anyone help me figure out why my starter relay keeps going bad? This isn't on my KZ900 but on my daily driver 1985 GPZ900. I replaced the 23 year old original relay with a new one from a local Kawasaki dealer. Two weeks later the same thing happened. I have 12 volts directly from the battery and when I press the starter button it sends 11.5 volts to the small wire on the relay but won't pass through to go to the starter.
I have tried taking a jumper wire directly from the battery to the small post on the relay but still nothing happens, no voltage going to the starter.
I bought another starter relay and it has worked for about one month. Now yesterday it is starting to act the same way. If I use a screwdriver to jump across the terminals it spins the motor over great and starts right up.
Battery is fully charged and not a problem. I have changed out the starter switch and the fuse box relay for the starter also while trying to troubleshoot the problem but still no luck.
Any thoughts or suggestions? Thanks!

do you mean the solenoid?bad electrical connection?its basically just a spring/plunger that closes when electricity passes through it aint it?

Yes, it is just a spring plunger setup. Connections are all good and clean, no corrosion. I makes no difference if I use the wire that is powered from the starter button or if I use a jumper wire direct from the battery. It still doesn't let the electricity pass through until I put a new one on and then it works fine?

ww2willys wrote:

Yes, it is just a spring plunger setup. Connections are all good and clean, no corrosion. I makes no difference if I use the wire that is powered from the starter button or if I use a jumper wire direct from the battery. It still doesn't let the electricity pass through until I put a new one on and then it works fine?

If you mean that the set of high current contacts (the side that drives the starter) keeps going bad, it means your starter is drawing too much current when it cranks and that fries the contacts.

bountyhunter wrote:
[/quote] If you mean that the set of high current contacts (the side that drives the starter) keeps going bad, it means your starter is drawing too much current when it cranks and that fries the contacts.[/quote]

Yes it is the side that drives the starter. The starter sounds normal and doesn't turn slow or drag. It does make sense what you're saying and I think that will be my next move to try another starter. Any idea how many amps the starter should draw?

ww2willys wrote:

bountyhunter wrote:

If you mean that the set of high current contacts (the side that drives the starter) keeps going bad, it means your starter is drawing too much current when it cranks and that fries the contacts.[/quote]

Yes it is the side that drives the starter. The starter sounds normal and doesn't turn slow or drag. It does make sense what you're saying and I think that will be my next move to try another starter. Any idea how many amps the starter should draw?[/quote]

Not exactly sure, I would hazard a guess of the ballpark of maybe 15 - 25 Amps?

Pull the caps off the spark plugs and crank the starter while measuring the battery voltage. If the starter is drwing too much current, the batt voltage will probably drop below 9V.

Maybe I'm reading this wrong, but from the symptoms I understand that the high current path from the battery, through the starter relay (solenoid) to the starter sounds OK to me.

I read the fault symptom as, the starter relay control wire does not operate the starter relay. Even connecting the battery (+) directly to the control wire does not seem to operate the starter relay. This sounds impossible unless the relay control wire has no return path to the battery negative (-)... or the solenoid is just bad. If the solenoid is good then this would make it a ground problem which is a lot cheaper than a new starter.

Sorry, don't remember if the ground is made by a clamp to chassis or a separate black wire. You should be able to test this easily. Disconnect the two big high current wires, disconnect the small control wire and small (black) ground wires. Connect the control wire and ground wire directly to a battery. You should hear and feel the relay operate. Put a Multimeter in the ohm scale across the big contact posts and it should read near zero ohms. If so all is good and you only have a ground fault to solve.

Or did I miss something here?

Best of success!

That's a good point, maybe your ground wire to the relay has bad connection of some kind, so check for 12v when the starter button is pressed on the one small wire, but also for zero volts on the other. This of course puts the 12v across the coil and magnet pulls the relay to connect the large posts to turn the starter. If the relay is really burning up repeatedly, this would be very unusual as I would think if the starter was bad drawing too much current, the battery would simply not turn it, not damage the relay but as always I could very well be wrong.

bill_wilcox100 Your description of the problem is right on the money and your wording makes more sense than how I described the problem.

The starter relay control wire is getting power. I was not sure if the other small black wire beside it was supposed to be grounded or not. In the electrical diagrams it shows that wire is for the starter lockout switch. I have checked with an ohmmeter and verified it is grounded.

Right now I have another good used relay that I used to connect the control wire and ground wire. Using the ohmmeter it shows the relay opens when I press the starter button. Each of the three times I've had a problem, the only thing changed out was the relay itself. As soon as a good relay is installed it starts like normal. Using the ohmmeter on all 3 old relays still shows no current passing through the relay when the starter button is pushed.

By the way, the last 2 relays were brand new from the Kawasaki dealer. I hate to put this used relay on and have it go bad in another week or two. The only upside to this is I'm riding my 76 KZ900 more often.

So... what happened?

Sorry, I thought I posted a follow up. After putting the used relay on the bike it only lasted a couple of weeks before it quit working just like the other relays. Did not want to keep spending money on the factory relays so the plan was to temporarily wire in a Ford starter relay and then replace the starter with one that I had just won from Ebay.
After installing the Ford relay, I have not had a single problem in the last 4 months of daily riding. The used starter is sitting here waiting to be installed if needed.

Another cheaper source for starter solenoids is your local riding lawn mower repair shop. I told a rider at www.kawasakimotorcycle.org/forumabout this and he went to the John Deere parts house and got a solenoid for $15 instead of the dealer for over $100.

He had to do a little wiring mod to make it work but no big thing. Sears sells parts for their mowers too.