Starts with "Run" switch

[Huey]

Not sure what is going on maybe a bad ground? When I push the run switch the bike starts and if I push start button the headlight goes out. I've checked the wiring near the battery also around the ignition,under both side scoops and I don't see any chafing or broken wires. Took apart the on/off switch and checked the start button and it looks fine. Just at a loss

 

[Fire-medic]

OK, what year is your bike? Is it new to you? Did you have someone 'work-on your bike?' Did you work on your bike?

I'm waiting for MaxMidnight to contribute the docs for troubleshooting electrical issues.



VMX12- Service-Manual.pdf (vmoa.net) Do you have a printed-out copy of this in your shop?

 

[Huey]

OK, what year is your bike? Is it new to you? Did you have someone 'work-on your bike?' Did you work on your bike?

I'm waiting for MaxMidnight to contribute the docs for troubleshooting electrical issues.

View attachment 84900View attachment 84899View attachment 84901View attachment 84902

VMX12- Service-Manual.pdf (vmoa.net) Do you have a printed-out copy of this in your shop?

It's an 88 and I've had it for years now I was told it could possibly be the starter stuck in the engagement position.

 

[MaxMidnight]

Have I got this right...you move the engine stop switch from off to on and the engine starts without touching the start button?

The stop/ sun switch gets a feed from the ignition fuse and in the 'run' position gives a feed to the starter circuit relay. The engine will start only if this feed is present.
The start button circuit is fed from a live feed in the starter relay and via the blue/ white wire to the switch and then to earth when the switch is pressed. When the switch is pressed to relay is energised and the starter motor turns.

So, if my understanding of the problem is correct then it would suggest there is a short in the blue/white wire that gives the the starter solenoid the earth when the stop switch is set to run.

Note that it is normal for the headlight to go out when the starter button is pushed and the oil and fuel level light to come on.

 

[Huey]

It's an 88 and I've had it for years now I was told it could possibly be the starter stuck in the engagement position.

Have I got this right...you move the engine stop switch from off to on and the engine starts without touching the start button?

The stop/ sun switch gets a feed from the ignition fuse and in the 'run' position gives a feed to the starter circuit relay. The engine will start only if this feed is present.
The start button circuit is fed from a live feed in the starter relay and via the blue/ white wire to the switch and then to earth when the switch is pressed. When the switch is pressed to relay is energised and the starter motor turns.

So, if my understanding of the problem is correct then it would suggest there is a short in the blue/white wire that gives the the starter solenoid the earth when the stop switch is set to run.

Note that it is normal for the headlight to go out when the starter button is pushed and the oil and fuel level light to come on.

Yes what you explained is what's happening. I'll have to trace the blue/white wire to see where the short is.Thank You

 

[MaxMidnight]

That's my best guess. I'd start by disconnecting the blue/ white wire at the solenoid end and use a multi-meter set to ohms, one probe into the blue/ white terminal the other on the frame earth.
If I'm right (no guarantee ) you should get a reading approaching zero.

 

[Huey]

That's my best guess. I'd start by disconnecting the blue/ white wire at the solenoid end and use a multi-meter set to ohms, one probe into the blue/ white terminal the other on the frame earth.
If I'm right (no guarantee ) you should get a reading approaching zero.

Thank You Sir I'll try that

 

[02GF74]

The engine turning would happen if the starter solenoid is closed so is supplying power to the starter motor.

Either the starter solenoid is powered, as described above (start switch earth's the ble white wire to close the solenoid) or it has failed in closed position - that should not happen as there is a spring inside to keep the contacts open.

If you are going to use a meter to check resistance, then disconnect the battery.

 

[Huey]

The engine turning would happen if the starter solenoid is closed so is supplying power to the starter motor.

Either the starter solenoid is powered, as described above (start switch earth's the ble white wire to close the solenoid) or it has failed in closed position - that should not happen as there is a spring inside to keep the contacts open.

If you are going to use a meter to check resistance, then disconnect the battery.

Thank you for the tip

 

[02GF74]

Resistance is measured by the meter injecting current and then measuring the voltage.

If the bike battery was connected and measuring resistance across 2 points ends up connecting the meter across the battery, at best the reading is incorrect, at worst the meter or something else may get damaged (meters usually have an internal fuse but that only comes into play when measuring current).

 

[Huey]

UPDATE *
Well after looking at my Blue/White wire that comes from my start switch I found that it was grounding at the point where it comes out of my handlebars. I would like to thank the people who commented and gave me a direction to look for possible causes .

 

[MaxMidnight]

Thanks for the feedback, glad you have it sorted.

 

[Fire-medic]

Yes, supplying feedback rewards those who have a similar issue, and use the search function to see possible causes as they look for fixes on their own problems. Nearly anything you may need fixed has likely been encountered and successfully conquered by someone else on-here.

 

[Stephan]

Very impressive diagnosis MaxMidnight! 100% correct. Absolute credit to the forum.