[BrunisPistol]

Hey all!

So I acquired my first bike, a 1981 GL500, about a month ago and have been loving learning to ride so far.

Today I had my first dead battery, and it is 100% dead dead - no indicator lights, nothing from the starter, nada. I believe I accidentally left the key turned to P and maybe that killed it?
After some quick googling i got a buddy to push me down the street and after 3 or 4 tries managed to get the bike running and keep running, but it was not well at all. It kept nearly dying even with the choke out and it was very sputtery and inconsistent sounding. After running a few minutes to warm up i tried putting it back in gear and got halfway down the culdesac before it died on me again, the battery is back to being 100% dead.

Previously it ran well (bit jumpy in idle but nothing too bad) and the battery was replaced only a couple months before i bought it.

How do i go about charging the battery, and is it normal for the engine to run so poorly after a dead battery like this, or did i screw it up by trying to push start?
My roommate (slightly more experienced rider, about 6mo experience) has a newer CBR500 and a trickle charger for that, can I use his charger somehow or do those only work for modern bikes?

This bike also happens to be my first vehicle of my own, and i don't have much more than a working understanding of engine function but i want to learn, so any pointers towards places to learn more about bike maintenance/repair would be much appreciated.

 

[Knute]

Get another battery.

When a battery is discharged that far, then it will not recover.

Do you know the function of the "P" position? It turns on the taillight. This was likely the reason you killed your battery. The purpose of the "P" is when you are disabled or need to stop on the road shoulder. The illuminated taillight will serve to warn other drivers as they approach.

Pointers for you.
1.) Download the Factory Service Manual (FSM) from the many links in member signatures. This is the gospel for these bikes. The FSM is written for Honda Trained mechanics, some intermediate steps could be missing.
2.) A companion book would be either Clymers or a Haynes manual. These are written for the backyard mechanic, many errors. Alway consult the FSM. These also have a nice color coded wiring diagrams.
3.) Once you have the FSM, perform the HIGH MILEAGE service list.
4.) Tires. Check the date code. If the tires have a 3 digit date code, then they were made before year 2000. Replace them. If the tires have a date code similar to XX11, these should be replaced. If the tires have a date code of XX12, then they should be replace in the next year or so.

 

[CaptainLiberious]

Unlike most other bikes I've owned the Gl650 will not run with a bad battery, something to do with the power for the ignition being taken from the battery instead of from the stator. So you cant just jump or bump start it and charge the battery with the bike, it won't run properly and will just foul your plugs up. And as Knute says when the battery's been fully discharged there's a fair chance it wont hold any charge after, I've had the same thing happen to a nearly new battery, let it go flat once and it was ruined. Saying that, I've had other batteries on bikes sit flat for months then charge up fine and hold charge. Anyone know why this happens?

So angry was I at my nearly new battery being ruined after going flat only once that I vowed never to use a bike battery again, and rode around for a year with a 600amp van battery strapped to the back seat. Man did that thing have some serious cranking power!

 

[Cobram]

If it's a normal lead/acid battery, you're lucky to get 3 good years out of it.
Take the battery out of the bike, tilt it back and forth to check the electrolyte levels, fill with distilled water if they're low, then do a slow bench charge.

That being said, motorcycle batteries are cheap, just buy a new one as already suggested by Knute in a previous post.