Electrical Woes. Short, Maybe

1981 kz550 ltd. old and ratty. I'm at least the 3rd owner, and the previous owners have definitely done amateurish maintenance work on it. As far as I know it has mostly original parts. The bike starts and runs, despite not being in tip top shape.

Prelude: Last Saturday, I opened up the bike and cleaned up some of the obvious nasty electrical connections. Got rid of a lot of nasty wire-to-wire connections held together by soldering and electrical tape. Replaced them with 3M connectors. Feeling good about making the bike more reliable.

The bike sat from Saturday through Wednesday and when I tried to start it on Wednesday, I can hear the starter solenoid clicking when I push the starter, but no engine turnover. This has happened before intermittently in the past and my old fix was to rattle te bike a bit, maybe tap on the solenoid area, thinking it may be a bad connection. Tried that, didn't work. Click the starter button a few more times, then everything died, including the headlight, neutral indicator, etc.

Thinking it may be a dead battery, I had it checked and recharged, not the problem. Checked the fuse and found the main fuse (AGX 20Amp) had burned out. Replaced it and was able to get it to where it was before on Wednesday. Ignition on, Headlight on, neutral indicator on, when I try to start the bike the solenoid clicks, after a few times, same fuse would burn out again.

After talking to some folks and mechanics, people think I may have a short somewhere in my system. To find it, I should replace the fuse, turn the ignition on, but not push the starter button, rattle the wires until I find a place that would cause fuse to burn out again then hopefully pinpoint the short.

Any thoughts?

The clicking sound is definitely from the starter solenoid. I also tried to bridge/jumpstart it with a wrench across the solenoid terminals. No engine cranking but had some sparking. Can it be a bad solenoid?

I also noticed the light gets dimmer when I push the starter button.

Check all battery connections, all must be clean and tight. One that gets forgotten is the Negative terminal(-) going to the engine mounting bolt.

Check the cable going to the starter motor from the solenoid for tightness too.

If the solenoid is determined to be bad, a suitable one can be found for a lot less $$ than the dealership sells by going to a riding lawnmower shop with your solenoid.

Keep in mind you may have add a ground wire to a solenoid mounting bolt to make it work.

Still no luck with this. Being a total noob at bike maintenance, I still cannot pin down the exact cause of the problem either. Is it a short? a bad solenoid? a bad starter? Pretty sure it's not the battery's problem since it was checked and recharged.

Pretty sure popping the fuse means I have a short. But does the fact that I only pop the fuse when I push the starter button mean anything? ie. fuse stays good forever when the ignition is on (lights on) and the engine is off.

Does the fact when I push the starter button I get dimming lights and zero engine cranking before I pop the fuse mean anything? The fuse only pop when I push the starter button multiple times and/or hold it down for awhile.

With the battery and fuse installed, I tried wrenching across the solenoid terminals. I got a lot of sparks, but no engine cranking. The fuse stayed intact. Does this mean anything?

I also tried removing my bike battery. Hooked up the bike to my car battery that I know is good (the car is off the whole time.) Turned on the bike ignition and the bike lights came on (good sign. The fuse stayed intact as well) but as soon as I push the starter button, the fuse pops.

Is there a better way to check for short? The method described to me doesn't make a whole lot of sense. If the fuse only pops when I push the ignition button, not sure how wiggling the wires when I'm not pushing button is going to identify anything.

Thanks in advance for any wise words. I'm completely out of ideas.

Here's link to wiring diagram found in Filebase under KZ Information (green ribbon near top of screen)

kzrider.com/index.php?option=com_docman&...d&gid=303&Itemid=108

From the diagram, am guessing bad starter or short somewhere in black wire or its connections between starter button and the starter solenoid.

Thinking this black wire may also route through an on-off switch controlled by the clutch lever and/or kick stand.

More suspicious of the starter itself due to fuse not instantly blowing when the starter button is pushed.
A direct short would instantly blow the fuse.
A bad starter might pull excessive current for moments until the fuse blows.

Just my armchair theory. :lol:

Good Fortune!

Have you had the switch pod that the starter button is located in off? If you have, it would be easy to accidentally disturb a uninsulated wire or damage fragile switch contacts. Also, this is a place where many electrical problems originate due to lots of wires, connections, and contacts in a small area that is exposed to the elements and general wear and tear.

+1 on the switch, check to see if housing has pinched a wire

Solved the non-starting problem. It was indeed the battery. It's an old battery that had died on me once before. The shop tested and charged it up for me and told me it was good.

My friend did a bunch of diagnostic test for me this afternoon, confirming the voltage and making sure the solenoid was working. He suspected that the battery wasn't outputting enough current to crank the engine.

He hooked the bike back up to the car battery again. Probably did a better job than me because when he did it, the engine started cranking when i push the button. Through the process in the past 2 days the fuse has not popped again, so it seems it might've gone away for awhile.

at least I can get the bike to start again. gonna go buy a new battery tomorrow.

thanks for all the responses.

Not so sure a low battery pops fuses, also be careful with using car batteries on a bike I seen a couple of electrical system fried