Bike not starting

[vampyre]

I have bought a 82 GS750T as a project bike. It only has 12,000 miles on it. The previous owner said he was riding it fine a few weeks before it died on him. He said it was idling and "all of a sudden it just died. " It will not start up at all now. Battery is fully charged, lights work fine. When I try to start it, I hear the relay clicking, and just a single click and effort. Almost like if you tried to start a bike on a nearly dead battery, where you can kind of sense something moving, or a vibration from the engine, but no luck. I have the Clymer Service Manual.
I checked the plugs, while they could use a change, they are not carboned, but the correct shade of tan. I pulled #3 and #4 out, and laid them on the head, grounding, and cranked. NO SPARK.
When I tested the battery, it is at 12V. I checked the signal generator by unplugging the blue and green wire harness under the right side cover, and checked with an ohmmeter, it was at 285 ohms (the manual says between 290-360).. i am assuming this is close enough?
I checked the igniter by removing plugs #3 and #4, and grounded them, hooked up to the wires still. I hooked up the red lead of the ohmmeter to the blue igniter unit wire, the black lead of the ohmmeter to the green igniter unit wire, with the ignition on. NO SPARK from anything. According to the Clymer manual (page 237), this indicates that I need to replace the igniter unit.
Can you guys confirm that seems to be the issue? Is this common?
Thank you so much for your help, as this is a sharp looking bike, and would love to get it running!

[Steve]

A bad igniter is possible, but go for the easy stuff first. Check your fuses with a test light or a meter, don't rely on how they look.

If your fuse box is like mine (on '82 650 and 850), There are five fuses. The bottom fuse is for the AUX tap screws on the bottom of the fuse panel. The next one up is the main fuse. The third fuse is for the ignition. The next one (second from the top) is for the brake lights and turn signals. The top fuse is for head light and tail light. If the middle fuse is blown, you probably wouldn't even get the single click that you do, but it's worth a check, anyway.

Another thing that is beneficial on our older bikes is to go through ALL the connectors in the wiring harness. Take them apart, spray some contact cleaner (Radio Shack is reported to be the best), then re-assemble with some dielectric grease to postpone corrosion.


.

[Redman]

I
When I try to start it, I hear the relay clicking, and just a single click and effort. Almost like if you tried to start a bike on a nearly dead battery, where you can kind of sense something moving, or a vibration from the engine, but no luck.

Vamp,

Lots of knolodgeable folks here willing to help.

By your description , do you mean it doesnt turn over when you try to start it? Just click-grunt, no wump-wump-wump-wump-wump-wump?
If its not turning over; the signal generator isnt going to generate any signal. So no need to troubleshoot the ignition yet, if its not turning over.

Please clarify.

Good that you have a Clymers manual, and that you have a volt meter. I think you will be using both.

.

[vampyre]

Thank you guys. Will check fuses shortly.
Just click, grunt...thats it. NO wump wump wump
just click,, then a grunt

[Redman]

Okay, so we are troubleshooting a starter motor/circuit problem not an ignition problem. Checking the fuses would be for an ignition problem.

Either there is two probelms, or PO is telling you a story.
PO says it was running then it quit. And you are saying it will not turn over, so it cant even try to start.

Anyway, back to the not turning over: You say you hear a click, so the starter button is pulling in the solenoid, so fuses realted to the starting circuits must be okay. The solenoid is what is clicking.
- But is the solenoid making good contact from battery to the starter? Can test by jumpering out the solenoid (the two big connections) with jumper cables, if that makes a difference then you know solenoid is not making good contact. Put jumper cable to starter motor terminal on solenoid first then make other connection to battery positive. If you were to put jumper cable to both connections on the solenoid; the last connection probably will arc and may mess up the threads making it hard to take apart the connection.
- Can try to cleaning up the battery cable and starter motor cable connections at the solenoid to see if that makes a difference. Try cleaning up both battery connections. Take apart and scrape/brush off any corrosion green stuff or white stuff.
- You say battery is charged cause you measured 12 volts. You have a battery charger? Put that back on for a while. Lights appaearing to work fine not a good test of battery. And you have a volt meter. Measure battery volts before and while tryiing to start it. IF volts drop way off, like to 8-9 volts then you can suspect a weak battery. Maybe try a battery from another bike.
- Then after the above you can suspect the starter motor itself. BUt since that is harder to change than the solenoid or battery, look at the other things first.

Tell us more what you observe. Many more here willing to help (but its way past my bedtime for tonight). My suspecision from a bike that you dont really know the history is the battery since those need to be repalced every few years as reqular maintance anyway.
.

[bonanzadave]

go for the easy stuff first.

Take a quick look at the oil level. If you had a petcock failure or leaky carb needle seats (alot of these bikes do. BTDT) you could have filled your crankcase with fuel.

[vampyre]

Update:
Probably is a weak battery. It has been on an automatic charger for a week, but when I try to start it, with meter hooked up, it goes from 12V to 6 V. I have a battery booster jumper box, but it needs to charge, so I will try that later. I am going to take a battery from another bike and try that, I know it works, I ride it every day!
Thank you so far, and will keep posting updates
Chris

[jbs80106]

After sorting out ur battery...

follow the electricity! You'll need either a helper, or tie something around the clutch pull to keep it engaged.

- follow voltage from the battery to the solinoid, check that you're getting voltage out of the far side when you press the start button.
- then (this is th PITA part) pull off your starter motor cover. on top of the motor, almost directly under the carbs. (probably have to move the carbs out of way to get to the bolts).
- check that voltage is reaching the starter.
- if you've got voltage there, then pull out the starter. getting the 2(?) screws out that hold it in place takes some figuring out but not too bad. Pull out the starter motor, leave it wired up, and hit the start button...if it spins thats a good sign. That it doesn't appear to spin fast enough or strong enough to turn the motor could be a few things....since your that far, take the starter apart and clean the insides....mine was coated in oil/dirt/gunk. Check the brushes...on mine they were fine, just needed cleaning.
- put it all back together and try again....

if no good, you'll need help from others. I've not had to go beyond this. I 'think' that even if the ignition was bad, the motor would still crank, but not start. Could possibly be compression thing or maybe something else in the motor (beyond my knowledge).

Good luck!

[Matchless]

OK, there you have proved it yourself! The battery! You can jump it from a car battery, but never have the car running at the time.

[psyguy]

The battery! You can jump it from a car battery, but never have the car running at the time.

this is how i burnt my coils... (no, the car engine wasn't running)

[argonsagas]

this is how i burnt my coils... (no, the car engine wasn't running)

Bluntly stated, it is not possible to to any damage whatever to GS bikes by using a car battery instead of the standard bike battery PROVIDED THE CONNECTIONS ARE CORRECT.

The bike needs 12 DC volts to start and run, and the source of those 12 volts is irrelevant.

A car battery has the capability and capacity to handle a higher amperage draw, but it does nothing else, and it can do nothing else, that the bike battery does not do.

[vampyre]

I bought a new battery for the bike, and have been charging it on a motorcycle trickle charger for about 2 days now.
Checked all fuses, they are all good. Cleaned the contacts that screw on the battery. The only difference is now, all of the turn signals light up, etc.
When I go to start it, I get the same CLICK, WHUMP. That's it. When the meter is hooked up, it is 12V, and when I push the starter button, it AGAIN drops to 6-7 V, like before with the other battery. At least the battery was only $25.
I am now going to do what jbs80106 suggested, following the electricity path.
Thanks everybody, and I will post updates.
Chris

[Big T]

Follow the advise on the starter when you get there.
They often get gunked up and a good spray down with contact cleaner (in a well ventilated place, if not outside) will degunk it and let it spin

The voltage drop is indicative of something shorting out. That would make the bike stop running

[DanTheMan]

Grounding, Grounding, Grounding. Make sure all your grounds are good!!!!!!!! I've grounded everything the the neg. post on my battery. No more problems. :-D

[vampyre]

Well, I finally got back to working on this bike. i am getting power all the way to the starter. Removed the airbox and carbs to get to it. Will be rebuilding carbs in a bit.
I pulled the plugs, and squirted WD40 down the holes, let sit for a day or two.
I can turn the crank with my 19mm socket one full revolution smoothly. It will only turn from 12 o'clock position, to 12 o clock position.
Is this normal? Should I only be able to rotate the crank under the stator cover ONE full rev?
Thanks!