Bike dies when running for 1/2 hour. Won't Power Restart Until Cool.

[jtischler]

I have a couple of odd problems. I have a 1981 GS550T. When I start it from cold, it comes to life almost immediately and after a few revs its good to go. Engine sounds sweet and even and idles at 1,100. Then, over the course of an hour ride or so, it will just cut out while running. Sometimes this happens at a light, sometimes while just riding normally. When I try to restart it with the electric ignition - no go. I have to wait 15-20 minutes and then it will start. If I am lucky enough to be on a downhill grade, it will start IMMEDIATELY from popping the clutch with no wait at all. What could be going on?

Second problem: When I start off in the morning, the ignition chugs to life with full battery power. But when I have been riding for awhile, if I stop or the bike cuts out on me, I have virtually no power in the battery and I'm praying I'm on a downhill or can lasso a nearby steer to pop the clutch and get going again.

Any help would be gratefully received.

[Steve]

From your symptoms, it sounds like your battery is going dead. Check your charging system.

.

[jtischler]

What about the hot restart issue?

Thanks for your answer. Even if I have plenty of battery, it won't restart when hot unless I pop the clutch. Does that sound battery-related to you also, or would that be another issue?

Why would that battery be fine when I start it up in the morning, but actually LOSE charge as I drive? Shouldn't it at least stay at the same level of charge?

Also, how would I test the charging system? I don't know very much about this branch of mechanics.

[spyug]

I'd also be suspicious of a failing coil.

Had this happen on a Yammie. It could be a break in the winding or at a contact. When the bike is cold the windings make contact and it runs as it should. When it warms up however the windings expand and the contact is broken. The bike stops running.

If you can get a spare coil, you could swap them out in turn to test this theory. The coil impedence tests may not show you anything unless the coil is hot when you test.

Just another thing to look into.

Good luck with it and lest us know what you find.

Cheers,
Spyug

[Buffalo Bill]

Oops! Bummer…for me too

I have a couple of odd problems. I have a 1981 GS550T. When I start it from cold, it comes to life almost immediately and after a few revs its good to go. Engine sounds sweet and even and idles at 1,100. Then, over the course of an hour ride or so, it will just cut out while running. Sometimes this happens at a light, sometimes while just riding normally. When I try to restart it with the electric ignition - no go. I have to wait 15-20 minutes and then it will start. If I am lucky enough to be on a downhill grade, it will start IMMEDIATELY from popping the clutch with no wait at all. What could be going on?

Second problem: When I start off in the morning, the ignition chugs to life with full battery power. But when I have been riding for awhile, if I stop or the bike cuts out on me, I have virtually no power in the battery and I'm praying I'm on a downhill or can lasso a nearby steer to pop the clutch and get going again.

Any help would be gratefully received.

That first problem I just can't scratch on my 550T. I've tried the relay fix but that made it worse! So I put in coils from a '93-1200 Bandit, but that didn't fix it. Frustrating! Next, I'm going to try cleaning all the contacts on the wire harness.
The second problem I did fix. I put a new stator in ($100), but that didn't work. Then I noted that the R/R was mounted to the battery box and didn't look to be well grounded, so I ran a heavy wire (1˘) from the R/R base to the battery Neg. and that did fix the charging problem.
Bill

[Buffalo Bill]

Buy the manual or download it…

Why would that battery be fine when I start it up in the morning, but actually LOSE charge as I drive? Shouldn't it at least stay at the same level of charge?

Also, how would I test the charging system? I don't know very much about this branch of mechanics.

If the generator system ain't workin' then everything is running off the battery. To test it put a voltmeter across the polls. With the engine off it'll read 13 volts. With the engine running and revved up to 5000 rpm it should read 14.5. If not find out why.
Bill

[Steve]

Even if I have plenty of battery, it won't restart when hot unless I pop the clutch. Does that sound battery-related to you also, or would that be another issue? ... Also, how would I test the charging system? I don't know very much about this branch of mechanics.

Yes, that could still be battery-related. Although it may sound like there is "plenty of battery", you need to check the voltage while the starter is cranking. If the voltage goes below about 10 volts, there is not enough there to power the coils enough to fire the spark plugs.

How do you test the charging system? With a voltmeter and the guides found in the Stator Papers.

.

[Buffalo Bill]

Starter sucks too much…

Yes, that could still be battery-related. Although it may sound like there is "plenty of battery", you need to check the voltage while the starter is cranking. If the voltage goes below about 10 volts, there is not enough there to power the coils enough to fire the spark plugs.

Hey Steve, any chance that the starter is defective and using too much power? Would replacing it fix the problem?
Would a bigger battery help? Except, too bad there's no room for a taller battery.
Bill

[nutsandbolts]

Yes, i think it could be a coil failing. Have the same issue an waiting for new coils.

[bobiii84]

The above posts are right when they say charging system problem. I've already used the stator papers about two months ago to track down a bad R/R (Regulator/Rectifier) and just two days ago I diagnosed a bad stator using the stator papers. Sounds very similar. I was riding and suddenly it died on me. I was able to push-start and get it home but here's what was happening. One of the three wires from the stator was shorting and not giving the battery what it needed. I was running off of only two wires giving me juice. Sounds to me like you may be having the same problem and if I were you, I would start with the stator papers. With a multimeter and an hour you can diagnose about anything on that bike. Good luck!

[Steve]

Hey Steve, any chance that the starter is defective and using too much power?

Well, that would explain the hard starting, but what about the "Then, over the course of an hour ride or so, it will just cut out while running." part?

Would replacing it fix the problem?

Only if the problem was poor starting. Remember? "it will just cut out while running".

Would a bigger battery help?

Again, only if the problem was "poor starting".

OK, if it's just not charging, a larger battery will let you get farther from home before calling for a tow.

.

[Buffalo Bill]

Well, I done it as well…

Thanks Steve,
I think I sorta hijacked Mr jtischler's thread and I'm sorry. He seems to be a new member and should post a hello in the GS Owners forum so he can get Bass Cliff's intro. But I lifted this for him in case he don't:

Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

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Thank you for your indulgence,

BassCliff __________________