Original Starter Button Question..

XS1204

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Hey all, I am putting together a 1978 650. Came to me in a few different milk crates. Parts of the original harness are pretty mangled and the LH control switch is more or less destroyed so I bought a TUSK wire harness that is a pretty universal setup. It comes with a all new LH control switch for signals, horn, Hi/Lo beam and you can turn the headlight off and on. It all is powered directly off the battery with an inline fuse and doesn't go into the original electrical at all. It is completely independent.

Now, I am installing clip-ons and finally read about the grounding through the handle bars starter button setup. I would like to still use the safety relay if possible as well. Now, I obviously can't wire in a grounding setup like the original so trying to come up with something that is safe and reliable. Where it runs through the bars to the LH switch then to a grounding wire I believe.

The only way I can get it to work is by putting a stripped wire from the RH inside housing and then run it to a black ground wire. The wire end is stripped to bare wire and placed in the RH switch housing making contact with the inside of it. The only thing though is the starter motor still kicks over even when I put the ON/OFF switch to the OFF switch and hit the starter button. When the ignition key is off everything is unpowered as expected so that works fine. So it works on both on and off positions.

So, hoping one of the gurus could give me a lead on what the best route would be here. I have a Hughs Handbuilt CDI kit I also will be installing. No Ignition system is hooked up yet. I have the original regulator and rectifier plugged in but the stock stator is out of the motor.


Heres the harness: https://www.rockymountainatvmc.com/parts/tusk-enduro-lighting-kit-replacement-wire-harness-p

Here is the new LH switch: https://www.rockymountainatvmc.com/parts/tusk-compact-control-switch-with-headlight-options-p

Again, running the original RH starter button on/off switch with an aftermarket LH switch that is completely independent from the original wire harness. It will get switched power from a keyed power wire though...

Thanks!
 
That's a lot to unpack all at once. To start with the starter button it needs a ground normally provided via handlebars (sent to solenoid on blue/white wire) - one idea to replace that, with clip-ons, is to run a ground wire with eyelet to the upper triple clamp and bolt it underneath somewhere. That will ground them, provided paint or powder coat are removed in the required spots. The horn button will also need to provide ground to that circuit.

The starter solenoid is normally powered via the ignition circuit, through the kill switch on the red/white striped wire. If it continues to be operable with kill switch off, the wiring has been altered. The light switch normally would not affect that circuit. The safety relay operates with 5VAC supplied by the stock stator via a yellow wire. IDK that Hugh's PMA/CDI will support that (ask him).

There is a wiring diagram for a stock '78 in the Tech section here as well as some "simplified" diagrams for various designs
 
That's a lot to unpack all at once. To start with the starter button it needs a ground normally provided via handlebars (sent to solenoid on blue/white wire) - one idea to replace that, with clip-ons, is to run a ground wire with eyelet to the upper triple clamp and bolt it underneath somewhere. That will ground them, provided paint or powder coat are removed in the required spots. The horn button will also need to provide ground to that circuit.

The starter solenoid is normally powered via the ignition circuit, through the kill switch on the red/white striped wire. If it continues to be operable to be operable with kill switch off, the wiring has been altered. The light switch normally would not affect that circuit. The safety relay operates with 5VAC supplied by the stock stator via a yellow wire. IDK that Hugh's PMA/CDI will support that (ask him).

There is a wiring diagram for a stock '78 in the Tech section here as well as some "simplified" diagrams for various designs
Thanks for the info! I have read a few of your comments to others that helped me out a bunch.

Yes, I put a lot of info in there haha. I’ll see what I can do about grounding the right hand handlebar for the starter button.

The horn is now operated via the new Tusk wire harness and switch. The original left switch is no longer in use.

I didn’t have the stator and yellow 5vac wire plugged in or on the bike at all for that matter so maybe that is why the safety relay isn’t working properly… I’ll double check the red/white wires to see if there’s an alteration. They all appeared to be in ok shape.

So I don’t need to run a single ground wire to the right switch itself. Just ground the right handlebar with some paint removed at the housing clamp area to complete the circuit.


As of now my main concern is addressing why the starter button still works even in the OFF position. Thanks again!
 
As of now my main concern is addressing why the starter button still works even in the OFF position. Thanks again!
I may not be clear on what is "off" and the starter still operable via the starter button....
 
I may not be clear on what is "off" and the starter still operable via the starter button....
The right hand control toggle run/off is what I am referring too. The switch is in one of the two off positions while still working...Ignition key turned on.
 
The switch below has engine stop on top (kill sw); that one should disable ignition and the starter circuit (button) when off (disconnects Red/white wire).

The light on/off switch in the middle normally only controls lights - switches red/yellow wire and blue wire. That switch normally will not disable the starter button

s-l1600 (4).jpg
 
The switch below has engine stop on top (kill sw); that one should disable ignition and the starter circuit (button) when off (disconnects Red/white wire).

The light on/off switch in the middle normally only controls lights - switches red/yellow wire and blue wire. That switch normally will not disable the starter button

View attachment 234105
Ok, yeah that is the switch. I’ll need to address the red and white wire to see why it still is able to turn over the motor in the OFF position.

Cheers!
 
One possibility is that the starter solenoid actuation circuit power - normally on the red/white wire from ignition coils - is getting powered from somewhere else. Should have r/w plugged into r/w at solenoid, but may have something else plugged in there
 
Don't try grounding the right switch to the triple tree, or anywhere else on the forks for that matter. They are not a suitable grounding point because they attach to the bike through the greased steering bearings. The connection will be intermittent and doing this can actually damage the bearings. Arching and small sparks may occur between the balls and races as they make and break contact, and that can damage and pit them. Instead, run a dedicated ground wire from the right control into the headlight bucket and connect it into the ground wires there that run back to the main frame. On the last couple models, Yamaha actually did this. Here's the right control from my '83, and you can see the ground wire they added attached to the mounting screw for the start button .....

83GroundWire.jpg


On the lower left, you can also see the two wires that run to the kill switch, a R/W and a brown. The brown is power in coming from the key and the R/W is power out running to the coil.
 
@5twins thanks for the info.

So I am not using the original lighting wiring as I installed a separate wiring harness and new LH switch.

I did what your pic shows. Since I am not using the orignal lighting setup I removed the RH switch light rocker switch. This gave me an open screw port that’s just like your switch. I ran a wire on a small eyelet from this screw thread to a black ground wire and everything worked great, except my starter button still works when the RUN/OFF kill switch is in the OFF position.

Now, I don’t know if it should still allow the bike to crank over or if it just doesn’t allow spark to ignite. Thanks!

For this bike I do plan to run the new ground wire from the RH switch to black ground wire though as your bike is wired.
 
Yes, I think the bike will still crank over with the starter if the kill switch is "Off", it just won't start because power to the coil is cut off and there is no spark.
 
Yes, I think the bike will still crank over with the starter if the kill switch is "Off", it just won't start because power to the coil is cut off and there is no spark.
Ok, perfect. I have a few Kawasaki’s and they simply don’t even crank when in the “off” position.

I’d like to remove the starter safety relay too as I’m not sure if my new electronics box under the seat will fit it…I got it to work without it. Not at my shop currently to see what I did but before I left I had the bike cranking without it.
 
Should not crank over with the kill switch off. I know my XS2 will not. The kill switch powers both the ignition and the starter solenoid coil.
 
The OP has apparently resolved the bar ground issue, but - just for clarity: the dreaded "arcing" through steering stem bearings occurs when no ground is provided to the handlebars and a button (starter, horn) is seeking ground, so it tries the steering stem. If a solid ground path is provided (to harness ground for example) via upper triple clamp, handlebar clamp or other means (given clip ons or rubber mounts); no arcing should occur.
 
Should not crank over with the kill switch off. I know my XS2 will not. The kill switch powers both the ignition and the starter solenoid coil.
Hmm 🤔 ok..investigation continues then. Cheers!
 
To bypass the safety starter relay, can I undo the safety relay and put the two red white wires together? One from the safety relay plug and the other from the starter solenoid? I’d like to get rid of it but understand the caution of not hitting the starter button when running. Cheers!
 
That will work.
Sweet, to confirm this will allow the starter solenoid to kick the motor over when the engine is running? Still need to figure out my cranking in the engine off position. Could’ve been how I was attempting to ground the switch.

Do I need to ground anything from where the original left hand switch went? Like a chassis ground or anything?
 
With the safety relay bypassed, the solenoid will be able to energize the starter motor, but the bendix gear will not engage (the crank is alreading spinning faster).

I'm not sure how your aftermarket LH switch is wired, the horn button may need a ground wire, or it may be designed to ground to the handlebar. The original LH switch housing did supply ground to the handlebar.
 
With the safety relay bypassed, the solenoid will be able to energize the starter motor, but the bendix gear will not engage (the crank is alreading spinning faster).

I'm not sure how your aftermarket LH switch is wired, the horn button may need a ground wire, or it may be designed to ground to the handlebar. The original LH switch housing did supply ground to the handlebar.
Ok good deal. Similar to some Hondas then as a lot of them in the same era never had a safety starter relay.

LH switch is now totally independent from the original wiring harness so I all good there then. Thanks again for your advice and providing info for me!
 
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