‘81 gs550 all electrics working except starter, help!!

[noaho]

Hi guys, just finished cleaning my carbs, rejetting everything and putting them back on my 1981 gs550t with individual pod filters. Went to start up the bike today, and when I pressed the start button - nothing!!

All electrics otherwise are working fine - gear indicator, turn signals, horn, brake light, headlight low beam and high beam. Everything except the starter.

before I took the carbs off all the wiring was working fine. Bike would start and was getting spark. The only thing I can think of is when I removed the front portion of the stock airbox I did have to remove some electrics that were screwed to the airbox, but I made sure to put them all back as they were before.

so, given all the electronics are working except my starter, any ideas what might be going on? Or where I should look for an issue? I’ve never worked with wiring before just as an FYI, so sorry if I’m missing something obvious here. thanks in advance!

[posplayr]

Did you check tehy Yellow/Green wire to the solenoid? It is connected using a bullet connector to the kill switch (start button).

If not, Jumper to the same wire from the battery to make sure the solenoid al least works. This would point to either something removed or bad switch.

[Redman]

Welcome to TheGSR.

You have a volt meter? How about a test light probe? Test to see if getting power to that yellow/green wire at the solenoid when hit the starter button.

You know about the kill switch...?

How about the clutch interlock switch...? (I am assumeing an 81 550T has that) (look under clutch lever).

Didn't take the ground wire (blk/wht) off from the solenoid mounting bolt did you???

[posplayr]

Welcome to TheGSR.

You have a volt meter? How about a test light probe? Test to see if getting power to that yellow/green wire at the solenoid when hit the starter button.

You know about the kill switch...?

How about the clutch interlock switch...? (I am assumeing an 81 550T has that) (look under clutch lever).

Didn't take the ground wire (blk/wht) off from the solenoid mounting bolt did you???

Yea I forgot about that, LOL

[noaho]

Welcome to TheGSR.

You have a volt meter? How about a test light probe? Test to see if getting power to that yellow/green wire at the solenoid when hit the starter button.

You know about the kill switch...?

How about the clutch interlock switch...? (I am assumeing an 81 550T has that) (look under clutch lever).

Didn't take the ground wire (blk/wht) off from the solenoid mounting bolt did you???

thanks for the advice! Yes have a voltmeter, will check tomorrow to see if I’m getting power when I press the start. If not, how exactly do I jumper the battery directly to that yellow/green wire?

in response to the kill switch, I have the kill switch on the “on” setting when I start it up so assuming that’s not it?

what is the clutch interlock switch and what does it look like? If it helps, I have the clutch lever held in when I’m trying to start it up, in neutral.

and for the ground wire, not sure about that but will check tomorrow. Hoping I did because that’s an easy fix! just to clarify, this ground wire gets mounted under the screw that holds the solenoid into its mount on the airbox?

thanks for the help guys !

[posplayr]

The solenoid is a simple device. It is powered from the Yellow/Green and grounds through its mount. Apply 12V to Y/G and it should drive the starter regardless of the key position.

The kill switch and the interrupting clutch switch simply block the 12V once you turn on the key.

[noaho]

The kill switch and the interrupting clutch switch simply block the 12V once you turn on the key.

So even without with the key inserted in the ignition if I wire the pos and neg end of the battery both to the yellow/green it should trigger the starter?

[Rijko]

So even without with the key inserted in the ignition if I wire the pos and neg end of the battery both to the yellow/green it should trigger the starter?

not both wires, just the positive.
There's a green/yellow wire, approx. 3" long coming from the relay.
It's usually too short to reach the positive terminal of the battery
so a helper wire may be needed, but tap that to the + on the battery.
Even without with the key inserted in the ignition, that should crank the engine.
Great way to quickly test the starter engine and relay.
If that works ok, troubleshooting the rest of the wiring is next.
Like measuring the voltage on the other end of the green/yellow
wire (with contact key and kill switch to ON) and pressing the starter button.

[noaho]

UPDATE!!! had some weird things happen today when testing....

I used some old speaker wire and touched the positive end of the battery to the the place on the solenoid where the yellow/green wire actually mounts. I also tried wiring the pos battery end to the actual bullet connector for the yellow/green wire and still nothing happened.

Using my voltmeter, here are some readings I got:

https://imgur.com/a/26ECuSs

the 6.23v was when the kill switch was set to 'on' and the 11.70v was when the start button was actually depressed at the same time with the clutch lever pulled in. So it seems like power is getting to the solenoid??

At this point, I was trying to identify the ground wire from the solenoid that you guys mentioned. On the front airbox mounts, there are three wires that are grounded to the frame and were like this when I got the bike from the PO. One of the wires comes directly from the neg end of the battery (blue tab on the end), and then there are two wires that are both black and white. Here is a picture of all of them:

https://imgur.com/a/MjRuKBz

One of the black and white wires that grounds to this point comes out of the same wire cluster, in the same direction, as the yellow/green wire to the solenoid. This is what I assumed to be the ground for the solenoid because it would be going in the right direction to mount to the solenoid mounting screw (I assume grounding it to the frame vs. the mount accomplishes the same thing??)

The other black and white wire comes out of what appears to be a split from from that wire cluster, but in the opposite direction as the previously stated wire and the yellow/green wire. There is not a black and white wire that comes directly from the solenoid body, so was confused about ID'ing what its ground is?

So here's when things got weird... at one point I removed the black and white wire I thought was the solenoid ground completely from the cluster of 3 grounds pictured above. I left the other two wires (all black from neg battery end and the other black and white wire) grounded to the frame. At this point, with the other black and white wire hanging freely THE STARTER FIRED!!!

With two tries in a row, the started fired. I quickly put the gas tank back on and connected the fuel/vacuum line and tried again - NOTHING. I attempted to rearrange the order of the two grounded wires, tired grounding all three again, tried different orders of the wires, and still nothing happened. I was not able to get the starter to fire again.

So, I'm a bit confused... I'm still getting approx. 12V of power to the solenoid based on my voltmeter readings when the start button is depressed, the kill switch does indeed kill all electricity to the switch, and so that part seems to be working. However, the solenoid is not firing the starter... but then it did when I removed the black and white wire I assumed to be the ground when the other two wires were still grounded??? So it seems like the switch, solenoid, and starter motor are all working but something is stopping them from working together... my gut says it has something to do with these three wires that are grounded to the frame since when I changed them at one point everything worked...

Any ideas guys? This seems weird and I'm hoping it shines a light on what the issue is.

Thanks!!

[Rijko]

I used some old speaker wire and touched the positive end of the battery to the the place on the solenoid where the yellow/green wire actually mounts. I also tried wiring the pos battery end to the actual bullet connector for the yellow/green wire and still nothing happened.

The result should be the same, could be a bad soldering, wire break, or bad connection because of corrosion. Does this work properly now - does connecting 12V to the bullet connector
activate the starter ?

[noaho]

The result should be the same, could be a bad soldering, wire break, or bad connection because of corrosion. Does this work properly now - does connecting 12V to the bullet connector
activate the starter ?

Pushing 12V to the bullet connector did not activate the starter. It only activated the two times when I removed one of the black and white wires (pictured in my previous post) from its ground to the frame.

If my voltmeter is reading 12V through the relay as it is, then doesn't pushing 12V from the battery to the bullet connector accomplish the same thing just in a different way? Sorry if I'm confused, but it seems like somewhere along the line the power is not getting from the relay (where it reads 12V) to the actual starter motor?

I'm just very confused as to why the three grounded wires I mentioned, when altered, ended up momentarily fixing the issue... voltage did not change, just removing one of the wires from ground changed things... so weird !

[Rijko]

Electrical issues can be puzzling !
That is why i try to focus on 1 thing at a time.

First, hopefully rule out mechanical issues and broken parts.
Personal preference is to try and get the starter system
working reliably.
The starter system, which i define as starter engine and relay,
is a good point to start but you could also choose to focus
on something else first.
Like making sure the green/yellow wire that connects to the starting
relay delivers close to 12 volt to the starter relay.
If you're lucky, it does so when pressing the starter button.
If you are not so lucky, which is quite common for these old bikes,
you're looking at checking the connection from the battery to the fuse box.
Next the connection to your contact.
Next see if the handle switch receives 12v on the kill switch,
and you may discover another common issue : the handlebar switch
may have corroded connections or pinched wires.
And so on.
You may have to do these things anyway.
Just don't try to do them all at once the first time, it may get confusing.
You may have several electrical issues at the same time, so looking
at the big picture looking for that one thing to fix all ... usually is not
the best approach.

See where i am going with this ?

[Rijko]

If my voltmeter is reading 12V through the relay as it is, then doesn't pushing 12V from the battery to the bullet connector accomplish the same thing just in a different way? Sorry if I'm confused, but it seems like somewhere along the line the power is not getting from the relay (where it reads 12V) to the actual starter motor?

It depends on how you are measuring 12 volt.
There is a big wire from battery + to relay.
That should read 12 volt.

That does not mean the green/yellow wire gets 12 volt, because the 12 volt from the battery goes through all the connections and switches and may deliver way below 12 volt to the relay, or none at all.

[posplayr]

Pushing 12V to the bullet connector did not activate the starter. It only activated the two times when I removed one of the black and white wires (pictured in my previous post) from its ground to the frame.

If my voltmeter is reading 12V through the relay as it is, then doesn't pushing 12V from the battery to the bullet connector accomplish the same thing just in a different way? Sorry if I'm confused, but it seems like somewhere along the line the power is not getting from the relay (where it reads 12V) to the actual starter motor?

I'm just very confused as to why the three grounded wires I mentioned, when altered, ended up momentarily fixing the issue... voltage did not change, just removing one of the wires from ground changed things... so weird !

That means the solenoid is not grounded back to the battery. In a stock configuration, there is typically a B/W harness ground (under the solenoid bolt) that gets back to the Battery(-) through some path that goes through the frame, back through the engine and then through the thick starter grounding strap. It is very circuitous and not very reliable. This is why a Single Point Ground (SPG ) is strongly recommended.


To start off put two wires:

1. +12V to the Y/G pigtail on solenoid and
2. the other to the ground the frame of the solenoid to Battery(-).

That should spin the starter. If it doesn't check the output of the solenoid to make sure it is applying 12V to the starter (the heavy red wire going to the starter)??

[Rijko]

So here's when things got weird... at one point I removed the black and white wire I thought was the solenoid ground completely from the cluster of 3 grounds pictured above. I left the other two wires (all black from neg battery end and the other black and white wire) grounded to the frame. At this point, with the other black and white wire hanging freely THE STARTER FIRED!!!

With two tries in a row, the started fired. I quickly put the gas tank back on and connected the fuel/vacuum line and tried again - NOTHING. I attempted to rearrange the order of the two grounded wires, tired grounding all three again, tried different orders of the wires, and still nothing happened. I was not able to get the starter to fire again.

So you may have found something that can be fixed.
Then again, it may be a coincidence since you were not able to reproduce
something consistently.
Maybe when mounting the gas tank and fuel line you disturbed a bad connection,
or the connection is intermittent as it is.

Baby steps, solving every issue one at a time, will get you there.
Electrical issues are common, the folks here on GSR have lots of experience
in solving them.
Whatever approach you choose, it will always be 1 step at a time.