'81 GS450: Dead battery after a few days - what gives??

[Anonymous]

So I got this naughty little 81 GS450 that is a bit of a trouble maker. :twisted:

Among other things, the battery goes dead if the bike sits for a few days -- I'm a huge moron when it comes to anything electrical.

Anyone have any ideas as to what is going on?

Thanks.

[snakebite]

either you have a bad battery or some accessory is staying on and running it down.
charge it but leave it disconnected a few days .
if ok its the bike.
if dead get a new battery.
i use a dmm in dc ma mode to find these problems.
lift the + and put the dmm in series with the system.
anything above 50ma or so is cause for an investigation.

[nabrams]

Your battery may be drained significantly after a ride due to a faulty charging system, but then you don't notice it till the next time you start the bike several days later. Re-starting immediately after shut-down may succeed (because of various reasons), while letting the bike sit for a few days may give it just enough time to lose enough charge so that it won't start.
Both my GS450 and my friend's GS450 had bad regulator/rectifiers. Test yours accoring to the steps outlined in the "stator papers" (found in the "Garage" section of this site). Basically, you want to see between 14.2 and 14.9 volts DC at the battery terminals while the engine is turning at 5000 RPM. If not, something is DEFINITELY wrong.

[snark]

Just a little personal note...The guy I bought my bike from was not at all mechanically inclined. He bought a new battery for the bike and charged it dry. Needless to say the battery wouldn't hold a charge for more than a week if the bike sat.