Topic: Bad ground maybe????

[Walt]

Hi,

I have a 1980 CM400T that sometimes when the ignition is switched on, nothing, no lights no nothing. I've checked from the battery to the switch with a meter and gotten 12 volts, thought maybe it was the switch, but every now and then when I turn the key, the lights will come on. The last time the lights came on, I hit a turn signal and the lights went out and wouldn't come back on.

Could a bad ground be causing this? I know bad grounds can cause lots of things, but I didn't think a bad one wouldn't even let the bike turn on.

Thanks,
Walt

[subkulture]

i would start at your ignition switch itself. it sounds like your ignition switch doesn't have very good contacts inside. that would cause the erratic behavior u described. you can get 12v to the switch but if it is corroded or has carbon deposits built up on the contacts inside,  you will see your symptoms. try unplugging the switch and bypassing it with some jumper wires and see if u still have random problems. if not, u found ur culprit. if yes, at least u eliminated the switch as a problem source. hope this helps. good luck

[TwoTired]

Have you cleaned the battery connections to the bike?

[Walt]

I had this problem about a year ago and thought the same thing about the ignition switch. Bought a new one and nothing. I think I ended up cleaning the fuse panel and behind it and everything worked, for a while anyway.

I looked at the wiring diagram and it looks like when the switch is on, the black and red wires are connected. I tried disconnecting the connector and jumping these two wires and still nothing.

The battery leads are very clean. The starter switch was a little corroded, but I took that apart and cleaned it and still nothing. Maybe I should take off the frame grounds, check them (they look clean) and reconnect them.

Between this and the 400F I have the oil light post on, my confidence in keeping these bikes running is dwindling. I know it's just something to work through, I just want to ride them right now though.

Walt