Motorcycle ignition

[jjmaia]

Hello there.

Since i don't have many experience in electronics, i wonder if you could help me with this "project".
I own a cbf 125, but it has a problem. The current in the electrical system is very unstable, so i wanted to know how to have 12v battery current on the circuit instead the unstable alternator current.

This is a schematic from a CBF 125, it must be similar to the CBF one:

**broken link removed**

What connections should i made so the electrical system has the battery 12v instead of the "unstable current" from the rectifier?

Thank you.

 

[Gary B]

I think you can do it by directly grounding the negative battery terminal. It is the same point as the green wire from the regulator. According to the drawing, the battery is only indirectly grounded through the starter. If you put a volt meter from the battery negative to ground is should read zero volts. Then switch to ohms. If you read any low value of resistance above zero, then that is where your problem is coming from.

Instead of changing the wiring, I would recommend that you find the existing bad ground connection(s) and fix it(them).

 

[jjmaia]

I don't think there is a problem, because a lot of bikes have this "problem". The "problem" is that the voltage is not 12v, but lower.

 

[Gary B]

Just because it is common, does not mean that it is not a problem. A poor ground connection will drop voltage across it reducing the voltage available to do useful work. Use the volt meter/ohm meter procedure to locate any poor connections and clean them up. I suspect that the problem will disappear with the unwanted corrosion.

 

[HiTech]

What Gary B states is the first thought that came to my mind also. It probably wouldn't furt to add a few ground straps (use old coax braid and wire terminals cripmed on them) to assure good grounds throughout the bike. Eliminate ground loops that often develop from a ground strap here and there failing over time.