my k100 was running like crap! come to a stoplight, and it sounded as if it would die out at any second. go to take off and it was running on two cylinders, then, 3, then back to 2 then finally "vroom" and off to the next light. i made the attempt at the most simple fix i could think of: removed the battery cover, tightened down the two poles,maybe getting a 1/8 turn out of each. then removed the "brain box" from beneath the document tray, unplugged it, shot some contact cleaner on all the little pins, and then dabbed each with dialectric grease. put it all back together, and the same thing. the next simplest thing i could think of to do was to charge the battery...left it on a trickle for about 4 hours, til the "green light" came up on the charger. hit the starter button and it fired instantly and settled into normal idle. took it around the block and down the highway...now it runs perfect again! well, as perfect as a 27 year old machine WILL run. moral of the story is to make sure there's a fully charged battery under the seat before starting to rip things apart. does this mean there's a weak charging system, or is it just the "nature of the beast"? maybe it has something to do with our 105 degree (F) heat here in sin city??

Just check the voltage at about 2000rpm it should be 14v +- .2v Then do it again with the headlight turned on. That is if you can turn the light off. With the light on it will probably be .2v lower maybe .3v

G'day diversity48 , sounds similar to a problem I had a while back ( running on two cylinders etc ) ended up being a poor ground connector on one of the coils , give that a geek while you are poking about .

JR

Melbourne Australia

we have noticed quite a few irregular voltages under running conditions out here in our neck of the woods ..of late ......some were associated with poor connectors at the back of the alternator /regulator ....and worth a pull apart and clean up .....with "deoxit" ....great stuff..

i wouldnt be surprised for you to find ...under load ..(headlights on ).that the battery volts were somewhere under 13 volts ....even at 2500-3000 revs

to me that doesnt seem to sound like a great way to look after a battery ...

good luck ...

been away from the site for a couple of days and just getting back. thanks for the replies! defintely some things to check out monday night. after that last battery charge, i rode it to work and about 1/2 way there (9-10 miles), it started doing the same thing again. i really think it's something electrical but havent had the tank off yet. the battery has plenty of power to spin it over, even with the headlight on...not the most technical measurement of battery power. i usually start it with the light off (it has the switch)... hopefully, i'll have some answers soon, and thanks again for the opinions! i'm thinking it might be heat related...ambient temp here when it started acting up was about 105F. i don't know how that would affect an already warmish motorcycle.