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Discussion Starter · #1 ·
Hi there. New member here. Have a 2008 cb250. Was idling and bike completely died, no power. Battery is good, but with key turn not even the headlight comes on. No clicking, no nothing. What should be my 1st, 2nd, third likely suspect?

May be a side issue - but in looking over the wiring, I noticed the connector that has fuses for the headlight and tail light only has three wires and an empty crimp point for a 4th wire. I can see no loose wire in the area to indicate a stray wire. Would the loss of this single connection point kill the whole dang bike? Appreciate any and all input.
 

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Discussion Starter · #3 ·
A touch over 12. Had no voltmeter, so i pulled the battery and threw it on a charger. When the lights still didn't come on, I bought a meter and the battery was good. Connections to the starter relay are good. I don't know how to test the starter relay or anything byond that. I'll be learning much from this, I'll predict.
 

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Discussion Starter · #5 ·
If that's the one that runs to the positive battery terminal, it was checked. But can check it again. The multimeter was what I bought. Bought the wrong kind of meter the first time. Bought the right one the second time...

Any thoughts on that side issue - with that fuse area for the headlight?
 

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As weird as it sounds, might just be the ignition switch, that wire could either come right off at bat+ or at the starter solenoid or relay, most likely another wire will be there also, that would be from charging system. Try going across the switch with a heavy wire or screw driver, if u suddenly get lights, your ig. sw. just ' bought the farm' It seems the main fuse by starter relay would connect to the ignition sw. so you can put a meter lead on ground and with other lead, check for 12V+ at sol/relay, then to fuse, got juice on both sides of fuse? good. what is color of that wire? does same clr wire show up at key sw?
DO NOT assume something can't happen. It could be that ignition sw. internally shorts to ground, that would so blacken a fuse, or as I said, sw. could just open even when key is in 'ON' position.

Did you buy from someone? if so you never know until you really get into it what is going on, a friend brought is bike to me, he bought 'used' same trouble as yours. turns out someone else put in an 'in-line fuse an buried it in harness, well fuse went along w/ all electrics so I undid all tape on harness and like wtf is this? put in new fuse an bike came back from the dead.What I am saying is with a bike from a previous owner, ya just never know what is what.


If a fuse is all blackish, it blew due to a short circuit, if it is clear and you see the melted link, than it opened on overload. if you have starter troubles, You put one meter lead to bat- and other lead to hvy wire to starter wire at solenoid or relay, when starter button is 'thumbed' u should get 12 v+. Sometimes a fuse will open but you can't see it cuz it opened, say next to the end, good practice, take 1 fuse at a time an check w/ ohm-meter, then you know, first though, touch leads together to make sure ohm-meter works, that is 'testing your tester' one can work on something for hours cuz they assumed there was a good fuse when there wasn't. Make a few accessories for your self, gonna need'em sometime. a few long wires like 14 gage, put crocodile clips on them. make a few short pieces, 6 inches long w/ clips u can use one to connect meter lead to ground as u probe around looking for volts or ohms. Be careful to dis connect one side of battery when checking for ohms otherwise u come to a 'HOT' lead and can damage meter.

Check it all, if no luck feel free to call me, 727 204 2767, If I don't answer leave a message.
 

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That is a nice looking bike.

Scratch that. Found the CORRECT 20 amp fuse, it was good.
Is it good because it LOOKED good? check it with an ohm-meter. if meter say's good and shows continuity, yup it is good

You say you put battery on charger, then checked voltage, a touch over 12.? is it an AGM type battery or can you see the cells?
if you can see the cells are they all covered with electrolyte?

I was thinking that battery may have been low, and even when bike was idling, not likely to charge at all till you get around 1500
to 1800 rpm and since not getting any charge, headlight, tail-light and ignition wore battery to point where it had not enough current
to keep bike running.

Let me know DoctorSteve, I'm willing to help you, if you want it. 727-204-2767
 

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Discussion Starter · #10 · (Edited)
Thanks for the input guys. Long story short, it was the battery until proven otherwise.

It was testing a touch over 12, but that was without load. as soon as I turned the key, it dropped to nothing. Absolute zero on the multimeter. New battery - started right up and maintained charge with key turned.

My only remaining concern is the alternator.

The dead battery was purchased last year, and kept on a charger (in an unheated garage in Buffalo, NY). It worked just fine for a use or two this year, but the fail happened on the way home from work (a ride that included considerable highway travel). So either:

1) the alternator is good (but the battery was bad and wasn't taking a charge, and it drained with no hope of resuscitation) or
2) the alternator wasn't charging appropriately and the good battery got killed by being drained.

(shrug)

or 3) something else.

I'll be monitoring battery health closely for the next few trips. Learned a lot. Thanks to all for the assist
 

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Well hello Doctorsteve,

Since the bike is running with a good battery, put the meter across battery with engine running and take note of battery voltage and at what rpm and write it down. subtract not bike not running battery voltage to see what the charging voltage is.

For the most part, the charging system is a magneto, where the power comes from is the stator and a rotor with magnets either spins over the coils that are wound on a laminated iron core or under them. the stator usually puts out about 20 volts a.c. for each thousand rpms of engine speed and is turned into direct current to charge the battery, more likely keep it charged once a fully charged NEW battery is installed on the bike. Another part of the charging system is the R/R rectifier/regulator changes a.c. to D.c. to charge battery AND to make sure the output is a couple of volts above battery voltage. They DO go bad, either cooking the battery or not enough voltage to charge, this will be evident of the starter not whipping the engine over as usual. The charging system is NOT designed to bring up a battery that is almost 'flat' Some think "I'll jump the bike to a good battery and once running, it will charge, yes it will but the BEST thing to do is put it on a battery tender for at least 48 hours.

Now the larger Honda's probably a Goldwing, those are alternators as they have a wound rotor that spins. A wound rotor has poles and a coil inside the poles as well as a pair of slip rings to which current is supplied. This alternator is VERY similar to a regular alternator for cars.The voltage regulator senses battery voltage and if bat volts are a bit short of 12, more current is applied to the spinning rotor or spinning field. the 3 leads from the 3 phase stator goes to a rectifier bridge changing a.c. to d.c.
 

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Discussion Starter · #12 ·
So if the manuals' stated idle speed is 1500 (+/-100rpm) I should expect output of around 30 volts, Ray? (I only ask, because there is no tachometer on the cb250, only an mph needle)
 

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Well Doc, what's the manual say the voltage of the stator should be? how many leads coming from the stator? if 2 than it is a single phase winding, same as what my Sporty has, 3 wires would be a 3 phase winding like the typical automotive alternator, I guess what I'd do is just put the meter cross the battery and
slowly roll on throttle and see what the voltage comes up to.

Does your multi-meter measure A.C. voltage? if yes then use it. if not,read below.

My service manual for the Sporty1200 says between 19 to 26 volts for each 1,000 rpm so as an idea I'd say around 40 volts at or around 1500, so if possible disconnect R/R from stator coils, maybe go to hardware store get a rubber bulb socket for regular 120 volt lamp the rubber one with two leads, black and white,
put a 60-75 watt bulb in and maybe you can get an idea of the voltage, Let me see if I can find out what voltage u should get at stator.
 

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Well Doc. I tried to find what the stator voltage would be, do you have a shop manual? if you are going to keep the bike, might be a good idea to get one, It is the only way to REALLY know what is going on, if in the meantime you can rig up a voltmeter you can glance at while riding, from what I saw 14.5 volts is a pretty good charge, 14 is good too. If you want, a battery tender is GREAT, it will keep the battery fully charged and will allow the starter to whip over the engine like you have not heard before, get the H-D battery tender, puts out 3/4 of an amp or 750/1000 of an amp, will NOT boil off the electrolyte. it comes with a two wire plug/cord that goes directly to battery terminals, all u do is plug charger in and hook cord to other end at battery. My wide glide always took about 4 or 5 seconds, to start, half that time now.
 
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