85 k100rs low voltage/charged battery

[117336]

Hey all. Been reading about all of the starter issues and wanted more info on ground running thru the starter. I have 11.25 volts on the battery and once in, will not even turn the headlight on. Acts like a drained battery. I read in a post that the ground is thru the starter and I need to pull it and clean it but should I be replacing anything (worn brushes?) before putting it all back in?

Also because of this will I need to tap the relay?
And will I do damage trying to jump from a car?

thx

 

[98lee]

11.25 volts is a bad battery.

How many volts does it drop down to when you try to turn on the lights??

 

[117336]

11.25 volts is a bad battery.

How many volts does it drop down to when you try to turn on the lights??


It read 9.8. Is it a bad battery? Or a combination of crud in the starter/ cold /???

 

[Neilkamman]

9.8 V is definitely a bad battery. Start by changing that out and see if problems go away. I have an 87 K75S and a new YUASA batt cured my cold-weather ills.

Normal (I believe) is 12.8 cold, and 13.2 running on a functional alternator.

There are good threads about this on K-Bikes.com.

 

[117336]

I have a 2yr old 12v BMW gel battery that has not had any problems till now. Have a battery tender and charge it monthly. Shouldn't it last longer?

 

[breyfogle]

I have a 2yr old 12v BMW gel battery that has not had any problems till now. Have a battery tender and charge it monthly. Shouldn't it last longer?

BMW branded gel battaries do not have a strong reputation. A 2 year life is not unheard of. They also require a charger specifically designed for gel batteries. If you want reliability, get a new flooded lead acid battery (BMW/Mareg or other maker). If you want convenience, get any of several brands of AGM sealed batteries.