Starter solenoid seeing low voltage at coil input.. Which/where are the connections?

G'day,

Bike = 1982 650 Maxim

Issue is that the bike had always been a bit of a pain to start - in my searchings today I've found that the starter solenoid isn't getting enough current to make the connection for the starter motor. The voltage I'm reading when hitting the start button at the two soldered red/black connections is 7.5V - when I check the battery voltage at its terminals I get 12.4V. Clearly there is at least one connection in the circuit that has a poor connection.

My question is, which connections should I be investigating?

I've tried jumping the battery connections to the solenoid and it kicks the starter motor.
Only 2 fuses are in the original box (PO changed them as they failed), and neither of them are the culprit. Tried the fuse holders that he installed and they all seem fine.

 

all of them. chances are there's more than one, it just hasn't given you problems yet

 

Fair enough - got lots of sandpaper and contact cleaner here.

I recently cleaned the ignition button, which made the starting easier until yesterday.

I have never pulled in the clutch to start the bike (i.e. with the kickstand up and the clutch pulled in the bike will not start) - the clutch switch does not appear to be seated properly in the clutch handle mount. I line the tabs with the holes and it pushes in somewhat, then stops on the next set of tabs. Am I supposed to twist and push here? I put a meter across the switch and it seems to operate correctly out of its housing.

I always just have the bike in neutral to start and used to have to sometimes hold the ignition button for a couple seconds, or turn the key off and on for the solenoid to fully make contact and power the starter motor. Makes sense now that I see such low voltage at the solenoid.

 

the two wires at the soleniod are not hot and ground unless your kill switch is set to run
there are 2 red/white wires running from your start button one goes to the fuse the other goes to the starter relay then to the solenoid
the blue white wire runs back to your kill switch then to ground

you should see 12 volts to the red white wire from the battery ground if low connections need to be cleaned.
you should see 12 volts to the blue white wire from the positive terminal of your battery to the blue wire when kill switch is set to run if not time to clean connections

 

this is the tell tale sign you need to replace the clutch safety switch

http://www.xjbikes.com/forums/threa...ed-a-new-clutch-switch-by-just-looking.30354/

 

Good info.

Never had an issue with just putting the transmission in neutral though. Where are the connectors I should be checking?

 

It seems to me like you are having trouble with the starter solenoid circuit. I don't have your wiring diagram, but I'm pretty sure it's the same in this respect: if you always start the bike in neutral, the circuit with the clutch switch will never be engaged. You can also remove the clutch switch from the body of the lever to accomplish the same effect, but then that circuit won't be protecting you (it will always see the lever as being pulled in to the bar). It is a normally-closed switch that the lever opens when it is disengaged.

Assuming that you're talking about the soldered connections on the start switch itself, then the connectors you need to check are (with the key on, see if the voltage reads close to battery voltage, or find out where you're starting to draw down toward 7V):

1. From the battery, through whatever connectors go to the main fuse
   
2. The main switch
3. The ignition fuse connections
4. The engine stop switch connections
5. Possibility that you have a bad diode, but I'd call that unlikely
6. Neutral switch

Make sense? Someone can correct me if I've made a mistake based on a different wiring diagram.

 

Wait I'm confused...I'm looking at the 650 wiring diagram now, and I'm not sure what "red/black" wires you're testing across. Can you specify?

 

My bad - was pretty dark when I was doing my testing. The wires I was testing are the two that are soldered onto the solenoid - red/white and blue/white.

I've checked resistance reading across the starter button across the kill switch and they seem to be in the sub 1 ohm which is good.

Where is the main fuse for the bike located? Should be a 20A?

Also where are the diodes located?

The solenoid does click when I hit the starter button, but voltage is too low for the plunger to fully make contact for the starter circuit just so I'm clear.

Cheers

 

Don't forget the internal contacts in the starter cutoff relay. You can temporarily bypass the starter circuit cutoff relay by removing it and installing a jumper in the socket to short R/W to R/W. Gamuru's starter troubleshooting guide has a nice diagram to get you there:

http://www.xjbikes.com/forums/threads/how-to-test-your-starter-circuit.7828/

There is typically a diode block within the head light bucket. They and the neutral and clutch switch would not be suspect for causing low voltage across the starter solenoid coil.

The starter solenoid coil draws about 3 amps of current, so just one ohm or resistance is going to cause a significant drop. Like stated earlier - Battery, main fuse, ignition switch, ignition fuse, kill switch, and then to high side of solenoid. Low side of solenoid affected only by wiring and starter switch, which applies ground to energize the solenoid coil.

Should be under the seat if it has not been modified.

http://www.xjbikes.com/forums/threads/how-to-install-an-aftermarket-fuse-box.6350/

 

I think you found a winner. If you are testing directly across the switch, when the switch is closed you should get 0V. Nothing at all. When it is open, you should get infinity. If you are detecting a voltage, there is a serious resistance in that switch. Take it apart, and see if it's all corroded inside.

I'm still a little confused about the wires...to be clear, I don't have a 650, I'm just going off the diagram and how my switches are. Someone with a 650 may chime in with different advice. Based on the diagram, I expect both wires on the starter switch to be red/white, but in any case, the statement about resistance seems like it applies.

 

if you test the wires at the solenoid you will be reading the voltage drop across the coil in the solenoid relay.
test from battery ground to red white will be 12 volts ground to blue white will be less that 12 volts.
wiring diagram first 2 links last link component list
http://members.tripod.com/dave_jack/wiringdiag/d7a.jpg

http://members.tripod.com/dave_jack/wiringdiag/d7b.jpg

http://xjdiagrams.thundervalleypower.com/wiringdiag/d8.jpg

 

Absolutely, that's why it's important to know which exact wires he's testing across. If it's on the connector (rather than the body of the switch) and it it is across blue/white and red/white, then I totally agree with what XJ550H said---that's just the coil voltage drop, and doesn't tell you a lot. You should do what he said to see if you have a bad voltage somewhere, that's true. You want to see almost the full battery voltage on the red/white. If you have a voltage drop across (from one side to the other side) of any connector, switch, whatever, then it's in bad shape.

 

I'm seeing 10.9V between red/white to ground and 10.5V from blue/white to ground - key on, bike in neutral

 

Is the solenoid serviceable?

 

Yes it can be taken apart.
1 de solder blue/white,red/white
2 make sure those small wires coming out of the case are loose
3 remove 2 small screws holding it together and take picks of your progress
4 clean and file the contacts inside
5 reassemble

 

Awesome - will try that tonight.

Otherwise I've picked up a 20A toggle switch - less than ideal/safe but I'm going camping this weekend and taking the bike.

Funny, after I cleaned up the ignition button and replaced some of the wire (PO was not great at soldering..) the bike will again start if I hold the button in for a couple of seconds. Oddly I'm still only seeing 10.5V or so to that harness that feeds the solenoid (solenoid unplugged). I would think that with an open circuit (not accounting for the very high resistance of my meter) I would see roughly battery voltage.

God damned gremlins...

 

Here is the result of testing the contacts that feed what I believe should be the starter cut-off relay

 

Info from the Ultimate Relay Switch Sensor and Diode guide provided by Len:
http://www.xjbikes.com/forums/threads/the-ultimate-relay-switch-sensor-and-diodes-guide.27543/

Starting/Ignition Cut-Off/Neutral Safety relay:

NOTE: all XJ700 models and XJ750-X models use a consolidated relay assembly (mounted under and to the rear of the fuel tank, on the wishbone frame triple-tube joint) which combines the turn signal flasher, the turn signal canceller relay unit, and the starter circuit cut-off relay.

Location:
- on all XJ550 models: in front of the coil rear mounting bracket.
- on all XJ650 Maxim/Midnight Maxim/RJ Seca models: under the gas tank, in-between the frame tubes, on a welded bracket just behind the flasher self-canceller relay.

 

So, my take on your voltages is that you have corroded connectors throughout. This is something I am working out on my own bike, and I have found that you can reduce the resistance in each connector to very little. I say this assuming that you have the key on when you measure those voltages (I think you have to or else you would get no reading? Can't remember). Anyway, you can bring the voltage closer to the battery voltage by cleaning the connections. I use a little bit of 1000 grit paper superglued to some 1/64" plywood, the kind used for making model airplanes and such. Just barely fits into the connector to polish the contact. What I believe is happening is that the wire that feeds the relay is getting drawn down by the other circuits (headlight, signals, and such). With lower resistances, this won't happen.

PS, not sure you should trust the resistances you measure with your meter. Your Fluke is doing a lot better than my RadioShack one, but still, the resistance can be more than it would seem when you actually have a few amps running through the circuit.

Hope I'm being helpful. Let me know if it seems like something else...but my vote is currently for cleaning connections, rebuilding relays, whatever it takes.

 

I appreciate your help guys I cleaned up a few connectors when I got home - starting seems to be working well - I just need to keep the battery volts up. Will continue cleaning until I've got all of them to mitigate voltage drop across the connectors.

Pygmy_goat - I f'in love my meter - was a perk from work recently :

http://www.myflukestore.ca/p5583/fluke_289.php

Would just about trust it with my life

 

Yeah, man, those are the best. I'm too cheap to buy one for home use, but if I needed it for work, I know which one I'd buy.

 

I love it - got it as a gift from Fluke when we bought one of these bad boys : http://www.myflukestore.ca/product/...rgy-analyzer?gclid=CLbI5pjB28cCFQIEaQodc7cKhw