1982 GPZ750 Starting issues

Disconnect the solenoid from the battery then test for a short.
Steve

Shorai is sending me a new battery. Per their tech that opened my old one, they said it had zero charge which was odd. It also had an electrolyte leak which they tell me is indicative of overcharge. I had my starter bench tested locally and it's as good as new so that isn't the issue. There is a new wiring loom on my kitchen table so I'll be replacing it this weekend.

And yes Swest, I will be removing the solenoid before I do anything else to test. I'm not going to throw money at the problem and I'm also going to be as methodical as possible.

swest wrote: Disconnect the solenoid from the battery then test for a short.
Steve

I actually took your advice one step further and disconnected the starter. Even though I replaced the brushes and nothing else, I just felt like none of this was going on until I did that. Well, with the starter disconnected, there is no short. The headlight comes on, blinkers, everything. So I found a good used starter and I'm going to give it a try this weekend so I can possibly ride the bike. The original starter will be going to a pro for a look at it to see what went wrong.

I installed the new starter this weekend and it was, without a doubt, the beginning of the issue. Now the starter turns over nice and crisp with lots of torque. Now the issue is that the starter won't stop. I had to disconnect the battery. I shut the ignition off and it continued to crank until I pulled the battery wire. I'm going to guess the solenoid which sucks because I replaced it just six months.

The same thing happened to an 84 fz600 I had a few years back. I sold that bike before I fixed it.

Ideas?

Get a new one. Some here got a lawn mower solenoid. Probably cheap compared to OEM I'm dubious on how long it will last. I use mine all the time.
Steve

swest wrote: Get a new one. Some here got a lawn mower solenoid. Probably cheap compared to OEM I'm dubious on how long it will last. I use mine all the time.
Steve

An oem will cost me 20 or more bucks and a shitty chinese version will run me about 10 bucks. I just wonder if it's the solenoid. It sure seems so...what about the starter relay? Remember, this thing is cranking with the key and run switch off. My starter switch is good; replaced it a couple of months ago when the original one pooped out.

That's what I'm talking about. The windings might be shorted or the main contacts could be fused together. Is it disconnected?
Steve

swest wrote: That's what I'm talking about. The windings might be shorted or the main contacts could be fused together. Is it disconnected?
Steve

No, It was connected when I reconnected the starter. It was fine at first and then just took off. There are two relays on the bike too...I assume one is the starter relay? Or is the relay part of the solenoid? When this happened, everything was connected as factory. Right now, the battery is disconnected and will remain so until tomorrow after work or until I can sort this out.

Edit: Perhaps I am making the solenoid and relay out to be two separate things when in fact they are the same?

They are the same.
Steve

You must have a pinched wire or wrong wiring somewhere. I have never heard of a bad solenoid that won't stop . By it's nature the usual failure is in the charged internal switch wearing out or being brunt up. You said you replaced the switch. If it starts cranking when hooked up my your wiring has defeated the start switch. My guess is you have a short that is constantly connecting both on and start at the same time. How it happened I don't know but that is what you are describing. Sounds like you have hooked the starter wrongly to constant power for both starter and run rather than keyed power from the switch. My $0.2. R

rrsmsw9999 wrote: You must have a pinched wire or wrong wiring somewhere. I have never heard of a bad solenoid that won't stop . By it's nature the usual failure is in the charged internal switch wearing out or being brunt up. You said you replaced the switch. If it starts cranking when hooked up my your wiring has defeated the start switch. My guess is you have a short that is constantly connecting both on and start at the same time. How it happened I don't know but that is what you are describing. Sounds like you have hooked the starter wrongly to constant power for both starter and run rather than keyed power from the switch. My $0.2. R

That makes sense but the solenoid hasn't been touched since I replaced the battery. Hell, I did nothing to the solenoid even after the starter shorted and caused my Shorai to melt.

Timeline: Bike ceases to start with new Shorai after about a month, charging is fine so no idea what was wrong. Checked starter switch on handlebars and found it broken, replaced with known good unit. No good, assumed starter, replaced brushes in starter (they were toast so I was on to something), hooked starter up, attempted to start bike (after battery had been hooked up correctly) and short occurs melting Shorai battery in a glorious show of steam and frightening sounds, disconnected starter, hooked up new battery which worked fine for headlight/signals/etc, replaced starter with known good starter, hook up battery and starter cranks without stopping unless battery is disconnected. While I know it is of little consequence, the solenoid on the bike is about 6 months old, perhaps less.

Well now I remember about the battery melt. You may have melted some wiring or the solenoid. I forgot you had free amps like that. The starter and solenoid are easy to bench test. You could take them off the bike and bench test those components with your battery and alligator jumpers. I don't think you'll find those components faulty. I bet u have melted something else in the wiring, the harness or switch. The switch could be hooked up right, but fried from your battery incident. Good luck.

R