This morning when I came in, there was a ZRX400 sitting outside.
No email or note explaining anything.
No accident or crash.
I installed something last month and wondered if there was a problem with the rear wheel, so I examined it carefully, but found nothing wrong.
So I just left it as is until the owner showed up.
The owner came by after lunch and said, “The power suddenly went out and it won’t respond at all…”
“The fuse isn’t blown.”
A few things clicked into place.
I start by checking the easiest places to diagnose first.
1) The fuse isn’t blown, but there’s poor continuity.
This is a blind spot—it happens more often than you’d think. Check the contacts and use a multimeter to test continuity.
2) The fuse in the starter relay section has blown.
Fuses exist outside the fuse box too, so check everything.
3) Poor contact inside the ignition switch or poor connector contact.
You can tell by checking voltage at the main on/off, but let’s look anyway.
4) Poor battery terminal contact.
Rain and wind cause moisture, and as electricity flows, it generates heat and creates a film on the surface, causing poor conductivity.
5) Actual broken wiring—this is serious.
With factory wiring, you rarely see breaks, but if someone’s been messing with the wiring, it’s possible.
That’s really a headache.
So the answer was #4.
Poor battery terminal conductivity. The terminals had turned light brown and looked pretty rough…
I polished both sides with a wire brush, reinstalled them, applied contact cleaner, and we were done.
The lights came right back on! Charging voltage is good!
So one less bike tomorrow—glad we got it sorted!
