Topic: CB550K1 : Headlight Gremlin or Normal?

[a_king]

Picked up a CB550K1 this last summer - PO had 2 (yes 2) computer backup batteries attached to it. Was running fine, but decided to grab a battery (UPG UT12C) from another of my bikes to have a *real* battery on it.

Put the battery on a tender overnight, tender read charged at ~12.7v.

Hooked it up, started the bike. About 15 minutes later, the bike had no getup, stumbling, etc. - turned off the headlight and *bingo*, back to life. Remembered the battery had been in the cold over the winter, so swapped for another. Same issue.

Checked voltage last night. Headlight off, bike idling at 2k, 13.5v at the battery. Turn on the headlight, jumps down to 12.5v and slowly ticks down to 12.4v, 12.3v, etc...

Checked connections in bucket, cleaned a bunch of them off, still the same. On a side note, checked coil & plug resistance, one coil was high at ~25k Ohms & the plug boots were all 7-9k, so getting replacements there.

What should I test next?

[a_king]

Or, maybe both batteries are bad?

[strynboen]

thek the main key..the back plastic part (vith konnektors) use to vear aut..and shorts/or cuts konnektion..or gets hot..
it often komes after some time riding..vhen it heat up bu korosion in the vires/konnektors...if you bay a new..dont bay emgo ..they get splitted up..i have glued mine...but NeXT time i bay a better alternative..
get a blade fuse block..even the old look fine..they often burnes up at the back side..so not to be seen...the glass fuses are also hard to find..aut in the real World(tank stations)..easy to thange...pull the konnejtor in main hareness..cut the old fuseblock aut..and konnek the new..vire for vire..
often stator ..regulator and reg  dont have any errors..viring korosion is main problem..so dont vaste  Money thange all parts to new ..before testing them

[a_king]

By main key, you mean the ignition?

[strynboen]

yes...

[a_king]

i guess i could check if there is a load to check for a short? disconnect ground from frame, measure from frame to pos terminal with voltmeter? would that tell me anything?

[strynboen]

yes but use amps messuring on that test...and DONT push the start buttom...it vill blow your instrument.

a small flow vill be miliamps...vhen alll are shut off...key off

..a big flow indikates a real short..or big user of power on...some bikes can not shut light off.
so thek first vith key off...and in mili amp posision on meter...if nothing is hot...thange to heigh amp areia..and turn the key..if light turn on..remove the fuse to light and test on..to find the short..eventuell take the coils off too (Black vire under the tank)..so you can test on vitaut them sucking power

you dont use posive terminal to test amps..use the negative terminal..and put the meter between the ground vire and negative terminal..then it messure the flov going through the meter...amps flow...

[a_king]

so, the initial battery (weird PO computer backup battery) didn't exhibit this problem, whereas the new ones do.

could this be an issue where the new battery requires more juice to charge, therefore taxing the charging system more & reducing the amount available to things like the headlights & the coils?