Battery problem? or Stator problem?

[rongant]

Hi there...
I finally got the swing arm bearings in my 86 GS750, and so I thought I'd tackle the electrical / battery issue i'm having...

The thing starts and runs just fine with a boost.
When running (on its own, after the booster cables are removed), Battery Voltage shows varying voltage, as low as 11.5 or so, up to around 13 - 13.5v.

Then, I turn the bike off, after several minutes of runtime, and it won't start,.. the horn is weak etc. Voltage is down to like around 9 volts or so after trying to start it (doesn't have enough power to even turn it over once..)

To me, this sounds like a battery issue (the battery is about 3 years old).
I am sure I recall somebody giving advice a long time ago, that if you disconnect the battery, and the bike stalls, then its the stator, but if the bike runs fine with the battery disconnected, then the stator works fine...

What should I do next?

thx

Dave
86 GS750es

[relic-rider]

Get yourself a new battery. 3 years is a lifetime on these batteries. Yours is toast. As to what kind, do some searching on this forum under batteries and see what others recommend. After you get the new battery in the bike, see how it goes. Do the tests on the R/R and stator to see if your charging system is still ok.

[fgh]

A three year old battery would be very suspect. You can try to charge it to see if it will hold a charge. Make sure the charge rate is 2 amps or less. If you don't have a battery charger connect the battery to a car battery with THE CAR ENGINE OFF and leave it for about an hour or so. If its starts the bike by itself after that it maybe OK. The advice about disconnecting the battery to test for a stall is bogus. GS's don't create enough current to keep the bike running until the engine is around 3,000 RPM's. They need a moderately charged battery to run at idle. If you've got a manual it will tell you how to check the charging system, if you don't go to the Garage section of this website. You'll need a volt/ohm meter. A economy model will run less $10.00.

What you should do next is:
1. Test the battery and replace it if necessary.
2. Check the charging system. Look in your manual or in the "Garage".

[rongant]

Thanks a lot... I was trying to avoid buying a new battery if it was the stator etc... but at $45 Canadian, that's not a lot of $$ to throw down...

i'll try the reg/rec. testing from the garage if the new battery isn't helping..