Weird Starter

[barrelguy]

Over the winter I installed a new handlebar starter switch from MikesXS. Worked fine. Recently I did the carbs and still the switch worked fine. The battery was old and crappy but it got the bile started with the charger connected. Now the fun part - I put in a new battery, turned the key, pushed the start button and nuthin'. Ignition and neutral lights came on, weak horn and signals so I connected the charger and still nothing with the key. Shorted the solenoid with the key on and it fired up nicely. Turned the key off and it just continued running. Had to choke it to stop it. Any words of wisdom out there? Thanks in advance.

[jetmechmarty]

MikesXS switch? It’s probably roached. Good used is often better than MikesXS parts.

[DiverRay]

Check ALL THE GROUND wires on the bike! Take the screw/bolt off, clean, put on some anti-seize or no-ox then re- install.
This is probably 60% of the problems with these bikes now. I would also clean every wire connection just to make sure all is good.

[speedlimit85]

The button breaks and the spring shorts out and keeps starting. Take it apart see if the spring it may be jammed out of place.

[speedlimit85]

Kept starting with the key off may also be another short.

[Radioguylogs]

Usually that problem is caused by the starter solenoid contacts welded together. You can easily check with an Ohmmeter

[Larrym]

I second what Jetmechmarty said about the Mike's XS switch. ( •_•)

If you had a used-but-good OEM switch then at least someone here could verify what wire(s) in the switch were connected and where in a functional/good setup for a comparision. ( ͡° ͜ʖ ͡° )

But since it's an aftermarket switch and that's the last corrective action you took before this "event"? (O_o)

I'm thinkin' they're connected and in a bad kinda way. (•﹏•)

Kinda hobbled here on my end because I don't know the model/year of your bike and the wiring differs from model/year to model/year... ( ｡-_-｡)

On some models when the starter solenoid is energized the red/white wire connected to it sends voltage to the TCI which then bypasses the coil ballast resistor and provides a higher voltage to the coils so there's that hotter spark for starting the bike. (^_^)

However... if the starter solenoid STAYS energized that voltage also stays and in your situation might just be the reason the engine kept running. (O_O)

I would suggest disconnecting the "new" battery and then testing with a multimeter to see if-

1. The starter solenoid turns OFF after being turned on.

2. The key/switch actually operates as a true off/on for the ignition power.

I would not do any "trial-and-error" run tests until I knew for CERTAIN that whatever caused the "runaway starter" was fixed.

HTH...

[DEEBS11]

I used these aftermarket XS650 switches. High quality and have been very reliable for several years/many miles. However, you have to map out the switches and splice them into your existing harness plugs.

https://www.ebay.com/itm/323921392821