Topic: CB125 6 volt system putting out 30volts?

[Billy Bones]

Hi folks, I'm new here. If this post should have gone somewhere else, just let me know.

I bought a CB125 for $300 last weekend. Only looked at it for a second, and it started and ran alright, so it came home with me. Lights didn't work. No big deal. So I checked the fuse and it was no good replaced it. That's when I realized there is no battery. Voltometer says around 12v at idle, and 30 when revved! Any ideas for me? Am I gonna kill the coil with this much voltage?

Billy

[kirkn]

What year 125?  The ignition / charging systems changed once or twice over the years.  In the early years, they were a 'combined' system, and they won't generally run without a battery without some fairly involved mods.  Later, the ignition was 'separated' from the charging/lights, and they'd run without a battery.  This sounds like what you may have.

If so, then it sounds like you're reading the charging voltage, which is independant completely from the ignition system.  In that case, you've got no worries.

So, what year?

By the way, welcome aboard!

Kirk

[Billy Bones]

Thanks Kirk! It's a '72. I am measuring the voltage from the wires where the battery would be hooked up if there was one.

[grcamna2]

Install a battery & then test it.running it w/o one could damage the rectifier.

[thrutheframe]

That rectifier needs a load on it to work correctly and yes no load can kill it.

[Billy Bones]

Thanks guys!!! I'll get a battery in there and see where I'm at.

Billy

[grcamna2]

Billy, It would be good to test you're Rectifier; do you have a Service Repair Manual for it ?

[Billy Bones]

Just got my hands on a manual. Hopefully get some time in on this bike soon.

[grcamna2]

Excellent ! 

[mono]

i was thinking about this and to me, it seems like you're just getting 24v for free.  hook up a TV and a blender to it.