Hi there,

My poor 1995 CB400 Super Four's headlight isn't working!

I don't know if it was working or not on the way to work, but at 5pm in England in pitch black it clearly wasn't!

Now I've got it home I've looked at it properly. The headlight doesn't work with the engine on or off, unless of course I hold in the passing light and then it comes on while the passing light is depressed! The big rocker switch between main and full beam has no effect and the blue light on the dash doesn't come on either. The blue full beam dash light does come on however when the passing light is held on.

So in this kind of circumstance, what is the most logical course of enquiry to work out what the problem is?

The indicators are working fine but they appear to be flashing little too fast. Could this be a sign of a fuse or relay issue?

Any advice will be gratefully received! :)

Okay guys I've done a bit of fault finding and it's all looking a bit strange.

So, I took the bike out to the gym today and the headlight was still not working unless the passing light was held in.

Once I got the bike home I found the headlight CAN be triggered on normally, by first holding in the passing light and then activating one of the indicators. From that point on the headlight will work in either dipped or main beam until the bike it turned off for a while. If I then turn it back on then after a while it defaults to being off again.

The indicators are flashing fast though so there is clearly an issue with the circuit.

I checked the fuses and they are all working fine.

I found the relay (clicky box) and it seems to be dry and fine.

Where would you look next?

Hi guys,

Charged the battery overnight and it made no difference (not that I'd expected to as the voltage was fine).

In any case, the headlight is staying on now of its own accord. I did spray inside the switchgear with WD-40 yesterday to see if that would make a difference.

So it all seems cured now. There is just one question remaining, are these indicators too fast? Approximately 2 ticks per second.

Would it fail an MOT?
https://www.youtube.com/watch?v=Ql5Nl_3IgMA

It does seem a bit fast what wattage bulbs have you got in and are all four working with the same sort of brightness.

The official speed for indicators for an MOT is between 60-120 flashes per minute so you might get away with it.