86 CB450SC starter button - electrical issue

[gitter]

Long story short, working on resurrecting an 86 Honda Nighthawk 450. Previous owner laid it down and let it sit outside for two years.

I currently have it running...ish but the issue I'm having is the starter button isnt working. If I jump the terminals on the starter solenoid it cranks right up, if I try and push the starter button, the headlight goes dim but thats it. Every once in a while if I hold the starter button down it will slowly crank over and sometimes start, but thats once in a blue moon.


Things Ive tried so far that havent fixed the issue:
checked the fuses
checked / cleaned all the grounds I could find - one on the right side of the motor and one under the seat
new starter solenoid (probably needed one anyway)
ran a jump wire from the starter button to the solenoid (circumventing the yellow/red wire that runs in the harness to do the same job)



So, I'm open to ideas....electrical is not my strong suit...

 

[295566]

have you disassembled the switch to make sure it's working properly? Aside from that, start from the battery and work your way downstream. You know battery and starter solenoid are good, so trace your way back that way. Possible broken/frayed wire in the harness, bad connector, or switch itself.

 

[auntiebling]

the switch contacts are likely corroded. honda likes to send a lot of current through that little starter button, the side effect is that over time (not even accounting for abuse and sitting around outside corroding) the contacts get gunked up and stop working.

if cleaning the contacts works, consider adding in a relay to take the load off of the starter button if you are planning to keep the bike. headlights would benefit from relays as well, there are kits available that would make it a plug-n-play scenario. for the starter you'd probably have to DIY it, but it isn't all that complicated.

 

[gitter]

I broke apart the switch and cleaned everything I could see, when I get some time I'll pop it apart and check again. If that doesnt fix it, I'll probably try and source a replacement and then start rummaging around in the wiring harness looking for shorts

 

[bobl]

Trace the path on your wiring diagram, then bypass the switch at the nearest plug. If the starter works fine on the bypass, then it's the switch. If not, work bypasses up and down the line.

 

[motomania2007]

Jumping the terminals on the starter solenoid and it starts fine, indicates a possible bad starter solenoid or bad control connections on the starter solenoid.

The starter button applies either 12VDC or ground to the starter relay control connections.

If lights go dim when you push the starter button, sounds like the starter solenoid is bad.

The FIRST thing I would check is load testing the battery.

If that tests good under load, then I would inspect all the control connections to the starter solenoid.

If that is all good, I would swap out the starter solenoid. You can buy a generic starter solenoid at any autoparts store for $10-15 and that will work just fine.

 

[gitter]

replaced the solenoid again with a quality one instead of a cheap amazon one from china, bike started right up.