starter solonoid

Hi
hoping for some help with electrical issues, i have a z13a1 which i am trying to start[i have had it running previously] the issue seems to be solonoid/ starter motor related but my electrical knowledge is minimal.
today i was cranking the engine trying to get it to fire but to no avail eventually the solonoid just made a clicking sound, assuming i had killed it i put a spanner across the terminals and the engine seemed to be spinning,when i removed the spanner i noticed the solonoid smoking at the same time i could hear the starter motor engaging even though i wasnt trying to start it and it wouldnt stop even when i flicked the kill switch so i disconnected the battery, looking at the solonoid it has actually melted by the terminal ,this is the second solonoid i have used so i am assuming the actual cause of the issue is elsewhere
thanks for any advice
Paul

It would be my opinion that the high-current contacts in the relay are burnt and creating high resistance contact, creating the issue you explain. I'd replace the relay, clean the terminal ends on the heavy gauge power cable going to the starter and would seriously consider pulling the starter and checking the brushes and commutators. ( I am not referring to Russian Potatoes !

Thanks Scotch i am going to get hold of another starter motor and try that because this the second solonoid that i have burnt out i am wondering if there is a fault with the ignition wiring maybe like a constant feed as previously stated electrics is not my strong point

<....."am wondering if there is a fault with the ignition wiring maybe like a constant feed....> I think you'll find the low current starter relay wire is OK. If there were a fault with it you'd find the relay not "clicking" at all when you hit the starter button. Changing out to another starter is a good option as you can clean the commutators, service the bearing and bushing, check the brushes and give the housing and winding's a thorough blowing-out before you install it. I've had my original starter relay apart several times over the years to clean the high current contacts. Currently it occasionally requires a second hit of the starter button to engage the starter. If this continues to act up I will replace. If I can't find a new OEM I'll buy the most similar/appropriately rated aftermarket starter relay I can find......and that will be a great deal less expensive then an OEM. For the most they're pretty much the same for terminals and connections, aside from current ratings
In my Opinion: Problems that start with intermittent starter engagement and subsequently get worse, are doing so because the high current contacts have become compromised. This is a result of too many long duration's of the starter button being pressed trying to get the engine to start.
example; The bike won't fire-up immediately so the "cranking" goes on and on and on....... The high current contacts in the starter relay heat up excessively and "voila". Burnt contacts. So, problems elsewhere now manifest into this issue; compounding the the already frustrated owner with another need to go through flow-charts and diagnostic mazes.

I agree with Scotch. If you have solenoid clicking and no starter engagement then likely you have high resistance across the starter feed contacts.

One thing I'd like to point out is that these contacts tend to arc on engagement and disengagement and the arc transfers material from the contact tab to the contact bolts and at the same time, due to the high current, the heat across the contact plus the air inside the contact will oxidize the mating surfaces of the contacts. The contact surfaces on the tab are silver and a common practice in the millwright trade is to clean up and silver braze worn contact tabs and reshape with a file and surface enhance with wet/dry emery paper.
One much overrlooked cause of premature solenoid failure is a high resistance in the starter switch circuit which actually energizes the magnet in the solinoid which pulls in the rod that engages the contacts. A high resistance in this circuit will weaken the force of the magnet and the contacts will not fully engage. When the contacts don't fully engage, the current draw across the contacts will be trying to cross over less surface area and increased heating of the contact will happen. this is more prevalent on motorcycles than cars due to the exposure of the ignition switch and starter switch to water (rain). So don't rule out the starter/ignition side of the solenoid.

The other cause of premature solinoid failure is over cranking the circuit when the battery is low. This again will have the same effect. Low voltage (weak battery) will produce less magnetic pull on the tab and again allow higher resistance across the starter contacts although in this case the lower voltage is also crossing the contacts so the damage is less than if the battery was in top notch condition.
Bottom line, if you suspect the solenoid, you'd better confirm both sides of the solenoid circuitry just to be safe.

Seems by coincidence my starter relay decided to start acting up. I knew what the reason was as I've serviced the solenoid before. (Much to the credit of the solenoid manufacturer - two screws and its apart.) This time, upon disassembly I came to a couple of conclusions regarding our solenoids. As you can see by the picture only about 1/2 of the stationary contact makes contact with the original "short" buss-bar. I discovered another issue. The hole drilled in the buss-bar ( to facilitate a bushing, potentially restricts (?) the capacity.of the batteries current, to travell through it. Essentially this makes the current travel through two narrow paths - one each side of the hole. When I examined the factory buss-bar I could see that it was bent slightly. I attribute this to the heat generated by the current going through it. It "'sags". This in turn further reduces the electrical contact area because now the buss-bar no longer lays flat across the two stationary contacts.
I decided to fix a couple of things. Started by cleaning-up the stationary contacts. Then turned my attention to the buss-bar. I had a copper heat sink from "something"? and it was large enough and of the correct thickness to cut two pieces long enough to make a new buss-bar that made full contact with the stationary terminals. When soldered together the total thickness was just over 1mm more then the original. More heat dissipation ! Because of the additional thickness I chose to eliminate the "bushing" that was used in the original. I think the idea of the bushing was to help prevent the solenoid-pin from binding in the B-bar, because it must 'float", by design.
Sorry about the fuzzy pics. Seems my camera lens on my cell phone was a tad dusty but they should be self-explanatory regardless
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