Wiring gobblins

[btxs650]

I have spent countless hours working on the wiring for a friend's bobber and can't figure out why the starter button only works intermittently. He has a 79 bike with a new 78 wiring harness (don't ask) that uses an aftermarket turn signal/light/horn button switch. He chose to go with no on/off switch too to complicate things, so it only uses the ignition key as a shut off. I wired the thing up using the diagrams downloaded from this site for a 78. Never could get the coils to work with the harness in any configuration so I wired them up direct. The bike kick starts fine. The starter switch worked at one minute and then nothing the next after making no changes. I checked all the connections and they seem fine. Even taped the starter button on while I messed with every connection and nothing. The button is activated by the blue/white striped wire off the relay and the hot wire on the ignition. I even tried bypassing the switch to see if it went bad (brand new) and nothing. Replaced the relay and nothing. The other strange thing is that with the key off and no lights on, the battery loses it's charge as if something was left on all night.
Any suggestions (other than chucking the harness and rewiring the whole damn thing)? He paid $90 for the harness and would like to make it work.

 

[Pandorasglocks]

If it is losing its charge over night I would investigate that before moving to the starter button problem. What I would do is get a circuit tester, ground the clip to the engine block and move throughout all of the wires to find what is drawing power. Draining that battery every night is gonna end up costing him more $$$. As for the starter, idk, are you using custom fuses or the harness ones?

 

[btxs650]

It is using the newer style auto fuse.

 

[retiredgentleman]

A common problem with the start push button not working, is the loss of ground to the handlebars. The handlebars are rubber mounted and are therefore not grounded. The start PB needs a ground on one side, and when the button is pushed it sends this ground via the blue/white wire to the starter relay. The starter relay has battery on the red/white wire.

On 78 and 79 years a ground is normally supplied with a black wire that comes from the headlight bucket (common ground in harness)and connects to the turn signal/horn switch. This grounds the handlebar, which the starter button can then use.

You can also run a ground wire to the bolts that mount the handlebars, if that is easier for you.

 

[btxs650]

A common problem with the start push button not working, is the loss of ground to the handlebars. The handlebars are rubber mounted and are therefore not grounded. The start PB needs a ground on one side, and when the button is pushed it sends this ground via the blue/white wire to the starter relay. The starter relay has battery on the red/white wire.

On 78 and 79 years a ground is normally supplied with a black wire that comes from the headlight bucket (common ground in harness)and connects to the turn signal/horn switch. This grounds the handlebar, which the starter button can then use.

You can also run a ground wire to the bolts that mount the handlebars, if that is easier for you.

The grounding problem makes perfect sense, but I've tried bypassing the switch altogether with no results. The starter button needs a hot on one lead and a ground on the other, right? The blue/white wire is suppose to be a ground from the starter relay to the starter button? There is a blue/white wire and a red/white wire coming out of the corner of the starter relay that don't appear to be hot.

 

[retiredgentleman]

The starter relay has 2 wires, blue/white and red/white. The blue/white should connect to one side of the start PB. The other side of the start PB must connect to ground ( i.e. negative side of battery).

The red/white from the starter relay should connect to the Safety Relay (which is on the right side of bike near the starter relay). There is normally no battery voltage on the red/white with the key off. Turn the key on and you should have battery voltage on the red/white wire.

I'm not sure which 78 wiring harness you have. The standard harness only had 1 fuse, while the special harness had 4 fuses. However, it does not matter which one you have. Battery voltage is supplied to the Safety Relay from the single fuse (standard) or from the headlight fuse (special). Make sure your fuse or fuses are powered up when the key is turned on.

 

[btxs650]

No voltage to the red/white with the key on or off. I've tried disconnecting the blue/white on the start button and connecting it directly to a ground wire and still nothing. I also tested the blue/white and red/white wires with a test light at the connector to the safety relay with the key on and no power to the red/white wire. Maybe a bad safety relay?
It's the standard harness with only one main fuse which has been converted to a newer style automotive fuse.

 

[msmary]

try cleaning the contacts inside the switch itself with an emory board. (thin nail file) gently! (borrow one from your girlfriend or mom) usually there is corrosion on the contacts itself

 

[btxs650]

try cleaning the contacts inside the switch itself with an emory board. (thin nail file) gently! (borrow one from your girlfriend or mom) usually there is corrosion on the contacts itself

It's a brand new switch.

 

[btxs650]

No voltage to the red/white with the key on or off. I've tried disconnecting the blue/white on the start button and connecting it directly to a ground wire and still nothing. I also tested the blue/white and red/white wires with a test light at the connector to the safety relay with the key on and no power to the red/white wire. Maybe a bad safety relay?
It's the standard harness with only one main fuse which has been converted to a newer style automotive fuse.

Checked the leads coming off the switch with the key on. One is hot when the key is on. The other lead coming off the switch goes to the blue/white wire and is only hot when you hit the button. The red/white wire coming off the starter relay is not hot. Should it be?

 

[btxs650]

The blue/white wire should be grounded before connecting to the switch right?

 

[Grinder]

Is the starter button switch aftermarket as well? There should only be one blue/white wire wire on the stock set-up.As stated before you must have 12v at the red/white wire on the starter relay with the key on. If your bars are grounded, when you push the starter button it connects to ground and sends that ground through the blue/white wire to the starter relay energizing it and sending power from the battery to the starter.

If you have some kind of aftermarket switch with two wires comming out, one of those wires would have to connect to ground and the other to the blue/white going to the starter relay, again with 12v at the red/white.

 

[XSLeo]

You said you didn't use the kill switch? In the stock wiring the kill switch provides the power to the coils and the starter relay.
As several have said the red/white wire at the starter relay must be hot. The blue/white wire on the starter relay runs to the start button. As the start button is pushed it grounds the blue/white wire. The blue/white wire does not ground anywhere but through the start button.
To test your start relay get a couple jumper wires. Unhokk both the blue/white and red white wires at the realay. Hook one jumper from the red/white wire to battery +, hook the blue/white wire ti ground, it should crank the engine.
Now plug the blue/white wire into the harness blue/white wire, with the hot jumper hooked push the start button, this should crank the starter.
Now hook the red/white wire to a battery hot after the switch. This should get the starter to crank with the switch on. but not off.
As far as the discharging battery you need to trace out your wireing to find the short or where you have some wires mixed up.

 

[btxs650]

Thanks for all the help. It turned out that I had a hot wire going to one side of the ignition switch and it needed to be a ground instead. Problem solved! Now there is something drawing power from the battery when the ignition is off. The lights only work off the ignition, so it can't be that. Will the starter relay, ignition switch, or coils draw power when the bike is off? Enough to drain the battery in a about 30 minutes? The relay is the only thing that is hot all the time. The coils are run through the ignition switch so they are not hot when the ignition is off.

 

[Grinder]

I have read that a bad diode in the rectifier can drain the battery. Try unplugging the rectifier and see what happens.

 

[btxs650]

I'll give that a try. Thanks.