Hey folks,


I have an 1985 k100 naked and i just put a new battery in her and the other day it just died on me......hooked up a charger and it said completely dead..hooked up trickler and it took a charge...my question is........what can be drawing the power where the bike would die while running? any common problems with this model?

An alternator that doesn't charge the battery??

As Rene said...check the output of the alternator (14 volts or there abouts) to see if it's supplying enough voltage to the battery, if you can get the bike running.

When the bike is running, does the charge light illuminate? If it doesn't, you may have a blown bulb?

You may have picked a dud battery from new perhaps?

The alternator is where I would start looking even a crook diode pack can discharge a battery.
Like Blakey said a blown bulb on the warning light can stop an alternator charging because it gets its initial excitement from the current the light draws.

Like the men said best place to start looking.

BIG D

thank you all.i will be checking the alternator and light this weekend.....as always...very grateful for all the help

Just to clarify when we say 14 volts output from the alternator that is only when the bike is running over about 2,500 revs, at idle the output will be under 12 volts probably.
Regards,
K-BIKE

ok........great info guys.now.i am a non mechanical person when it comes to this bike............which light is it on the cluster and where is the alternator? thanks

The charging lamp has a battery symbol beside. Alternator is on the right side, above the gearbox.

Inge K.

"Alternator is on the right side, above the gearbox"

You will see a black "triangular" shaped piece of plastic (held on by 2 hex-head screws).
Remove this cover for a better look at the alternator.

It might be a good idea to go to a decent cheap tool warehouse and buy yourself a small digital multimetre which will give you DC volts and a whole lot of other things you may or may not need to know. They're useful and in America you can find a cheap but effective Chinese-made one for under twenty bucks, easy. I bought two and compare their readings. Or go for a 'Fluke' brand for a lot more, but it is better. They'll make your new-found electrical life a helluva lot easier. They may look slightly intimidating to a novice, but they're really quite simple to use. Cheers!


This is the very brand I bought and it cost me less than ten dollars five years ago in Tacoma, Washington. I'm still on the original batteries, the both of them!

So my three dollar multimeter from flea-bay is a bargain?

It's red (so it must be good), numbers appear on the display when I poke electrical things with it and it fits in the rear cowl of my bike...so I'm happy with it.

That's what's needed. Mine are red (like my bike) too!

I second the multi-meter. It has been an invaluable tool in diagnosing electrical problems. I just replaced my alternator with a 50amp model from a 1993 K, when running at fast idle of 1400 rpm it charges the battery at 13.95 volts. It bolts right in and I got a used model shipped to my house with larger cables for 165.00 USD.