Alternator wire melting

[cb400joe90]

Hello all,


Long and short of it is the bike had little use since last oct. I fitted the carbs back and went to work on the bike yesterday. Within minutes I could smell smoke and the 3 yellow wires coming from the alternator were melting at the connection. I have fitted new wire and made good connections. The battey is not getting charged as the volts dont raise above 12v. I followed youtube guides and tested the mosfet R/R and that checked out fine.

1. I have traced the 3 yellow wires going back to the alternator. I want to check that all 3 wires are connected properly. When I was refitting the carbs alot of pressure was places on the airbox which may have crushed/servered one of the 3 yellow wires. Can I use a multimeter to check if these wires are ok? If so what settings to use and what should the reading be?

2. This could also be a possible cause. Im not 100% sure I have the ignition coils connected correctly. The only guide I could find was a guide for a 250 hornet. How can I find out the correct connections for my cb400 super four NC31? If these are connected wrong could this cause my alternator wire overheating problem?

[bikemonkey]

http://www.electrosport.com/media/pdf/f ... iagram.pdf

[cb400joe90]

Thanks bikemonkey.

Ok here are my findings.

1. I With the multimeter connected to the battery terminals I get no increase in voltage when I increase the rpm. It stays around 11.8v.

2. I have checked the resistance between the 3 yellow alternator wires. I get a reading of 0.6 ohm. I then checked the continuity of these 3 yellow wires to ground (on the battery ) and I get no reading.

3. When I have the alternator connected back together and start the engine, I insert the multimeter into the connector. From watching you tube guides I should be getting 50+ volts showing up on the multimeter but I dont. it stays at 0.

I have removed the stator coils from the engine and inspected it. There are no major discolorations on the coils? small bits of that hardened substance have chipped off the copper coils but not much.

I should also add that I fitted a Mosfet type Reg/Rec over a year ago which worked fine. I also followed a you tube guide on testing a RR with a multimeter and my RR came back with good readings.

Any ideas? Is it the alternator/stator? I need this sorted asap as I have just renewed my insurance and every week I commute in my car it costs an extra €30 in fuel

[bikemonkey]

You've lost me there.

I have no idea why it's not outputting any power, all the other checks appear to be normal.

Maybe someone with more knowledge than me will know

[cb400joe90]

It turns out the positive wire connecting to the battery had come loose under the shrink wrap. Its sorted now and the battery is charging again.