Topic: The Ever-Popular CB650 bad charging 'issue', formerly hot start 'issue'

[TwoTired]

You have to get that Black -White rotor/field coil resistance somewhere in the 5-7ohm-ish range.  Certainly NOT 25 ohm.  The rotor needs current to make a strong magnetic field.  weak field = weak output.

Best if you can actually measure where that extra resistance is located.  So when you eliminate that, you gain confidence of a specific fix and reliable repair.  If it goes away mysteriously, you will always have some doubt, and possibly some issues with trust of the machine.

Cheers,

[leekellerking]

OK. BTW, the shop I have been getting brushes at is a small, mom & pop operation, that specializes in automotive, and when I first called about getting the Toy starter brushes, they told me, up front, to just bring in the old brushes and they would match them up. They didn't give a "fat rat's ass" (to quote my sister) what they came out of....

My kind of place!   

I'm taking tomorrow off so I'll call around.

[leekellerking]

Forgive my ignorance; I jumped into this thread thinking it was a rotor-brush related charging issue, like with the early DOHCs. Maybe I was wrong???

Scotty, this topic is much broader than just brushes (my Bikey's current issue). 

We touch on all areas of "damn 650 wont' start/run/keep running" here.   

[Frankenkit]

Lee, I'd say your bike's narcolepsy is worse or at least more frustrating than mine's unwillingness to wake up from naps.

[scottly]

Mickey, could you get a picture of the slip-rings? TIA

[Hush]

Ah bike porn....show me your ring!

[Frankenkit]

bohf of 'em.

[MickeyX]

Will have to be tomorrow. I got sidetracked on tapping out the dent in her new-to-her tank for the 350. Sorry. The tank, however, looks goooood. 

[leekellerking]

Okay, I ordered the brushes -- $19.95 (with free UPS shipping) from Rick's Motosport Electrics.

We will see if THIS fixes the problem.

Lee

[Frankenkit]

Well, I scoured the sliprings with some steel wool, the resistance between them was fine and normal, squished on the brushes a little and tested them- their resistance was normal, something pinches sometimes when the alternator cover is on too tight- resistance goes from 6.4 (normal) to 10.8 (too high) so I wiggled everything around until I could tighten it all down and keep the 6.4 resistance.  I think something still just got pinched or something. 

After a nice long ride, it starts up but still cranks slow.  Battery voltage after a long hot ride was 12.74.  still cranked slowish but enough to fire up.  Someone on the CB650 forum replaced the wire going from battery positive to the starter solenoid with an 8g wire with crimp-on ends and that solved the problem for them.  Seeing as mine is an old one from Sampson because my original one was savagely assaulted by the PO, I may do the same.

[Hush]

Hmm could be a bad connection on that wire Kit, try it as a cheap experiment.

[scottly]

Okay, I ordered the brushes -- $19.95 (with free UPS shipping) from Rick's Motosport Electrics.

We will see if THIS fixes the problem.

Lee

Lee, please measure the length of the new brushes for future reference, and also compare to your old brushes.
Kit, did you happen to notice how long your brushes were, compared to when they were new?

[Frankenkit]

The old ones were barely worn compared to the new ones I installed, practically the same amount past the wear limit line, but I replaced them anyway because they were old and the springs had gotten a little weak.

[scottly]

Well, I scoured the sliprings with some steel wool, the resistance between them was fine and normal, squished on the brushes a little and tested them- their resistance was normal, something pinches sometimes when the alternator cover is on too tight- resistance goes from 6.4 (normal) to 10.8 (too high) so I wiggled everything around until I could tighten it all down and keep the 6.4 resistance.  I think something still just got pinched or something. 

Something not right here... Do the brushes move freely in the holders? Are the brush wires dressed to allow free movement when the cover is on?

[leekellerking]

A picture is worth a thousand words.





Can you tell which photo is of the new brush?  :-)

Okay, I ordered the brushes -- $19.95 (with free UPS shipping) from Rick's Motosport Electrics.

We will see if THIS fixes the problem.

Lee

Lee, please measure the length of the new brushes for future reference, and also compare to your old brushes.
Kit, did you happen to notice how long your brushes were, compared to when they were new?

[scottly]

Yup, that looks like a worn out brush. I'm guessing it was the out-side brush. What about the other one, the in-side brush? I'm also going to guess it's not as worn..
Hope you have gotten your problem fixed!!! 

[leekellerking]

One step forward, one step back.  I finally got off my fat ass and installed the new brushes; buttoned up Bikey, and he wouldn't start. 

Looks like a bad solenoid.  I can start him by shorting across the terminals of the solenoid, but that is NOT a good long term solution. 

Argghhhhh.

Oh, well; at least I've got the Yamaha to ride to work.


Lee

A picture is worth a thousand words.

[Frankenkit]

we did things the way we usually do them, two or three at a time.  I cleaned the starter motor (didn't need much cleaning, was practically new) replaced the cable from solenoid to starter motor, and we retarded the ignition maybe a millimeter.  MickeyX took it for a 15 mile run around and through which was usually enough to get it to not start again and it started without a second's hesitation.   That's good for me!

[scottly]

 

[Frankenkit]

Edit 5/4: I can confirm this... I rode 'round town, to the store and back, and when I left the store, she fired RIGHT up.  Surprised me a little, even.  I stopped for gas.  Started again. Right up! No dicking with the throttle, no she was just fine, thanks!  

The more I think about it the less I'm absolutely sure which it was, but it was definitely between retarding the ignition a little and replacing that solenoid/starter motor cable.  I'm very inclined to blame the cable, however, because it was very twisted and mangled looking, compared to the new one.

[Hasenkopf]

yep, over advanced ign timing often mimics another problem, at least with those 70's cars (don't ask!)       glad you got some results...finally !!!

[Hush]

I got my fingers crossed for ya babe.

[MickeyX]

What, you didn't believe me when I told you she starts right up now? Hmmm. Women. 

[scottly]

I'm betting on advanced timing, too. If you're curious enough to prove it out, replace the old cable and see if the problem returns. Then again, if it ain't broke.......

[Frankenkit]

exactly.