Vintage Dirt Bike Q & A

I am still working on my 1974 MT125 and I am now to the electrical trouble shooting of the lights and why they are not working...by the way I hate electrical problems... I know I bet I'm the only out there that hates electrical problems.

The rear right tail light faintly works, the left rear turn signal light doesn't work at all, the front turn signals work and are bright but will not flash. The headlight and the bright beam light on the headlight bucket doesn't work. I did test the headlight and it comes on when directly hooked up to the battery so I did eliminate the sealed beam. I have looked at the connections and they seem to be OK and I can't tell if the switches are OK or not and that's why I'm writing this post.

Is there a way to check to see if a switch is working properly? I have looked online and to buy both switches is nearly $100 and I really don't want to spend that just to find out that mine are good or that isn't the problem. One more thing you might need to know although I don't think it is the problem is that I replaced a missing ignition switch from eBay but it plugged right into the wire harness and all the instrument lighting is working and the tail light and brake light work as they should.

Thanks again for the help,

Keith

Faint or barely working could be a bad ground wire on the bracket or wrong bulb.
To test the switch you can use an ohm meter with the switch disconnected or a dc volt meter with the switch hooked to the harness and key on.

The headlight will only come on if the bike is running and if your stator is working.

The winker relay may be bad if the signal lights dont flash. A 6 volt signal flasher is all it is. Just make sure your wiring is hooked up right. Mine doesnt use the green wire in the harness.

Thanks for the info, I assume by your user name you are from OK. I am just across the border in Kansas near Wichita.

I was looking at it last night and have everything working except the left rear turn signal and it doesn't have power coming from the wire harness. I did have that big mallet hit me in the head last night and I had started the bike to adjust the carb and to my amazement the headlight and high beam light were working great. It didn't even dawn on me they would be running off the stator and not the battery...hit me in the head again!

Again I appreciate the help and it's fun fixing a problem or discovering you don't have a problem by mistake.

Keith