turn signals turn off while down shifting

[84Seca]

I have a 1984 Yamaha Seca xs400, I have noticed that when I turn a corner my turn signal will turn off right before I turn. I noticed that my blinker switch was a but stiff so i took it apart and cleaned it up, but still no change. It seems that it could be related to either time or vibration from down shifting. Sometimes when I don't down shift to slow down, it will stay on, but sometimes not. There is no definite time it will turn off. Any ideas?

 

[Scorpio1963]

The only thing I can think of is a bad switch which also may be a part of my problem.I go to turn my signals on and the switch wont stay in place its keeps moving back to the off position.
Other than that you have loose connection to the ground wire somewhere within the relay for signals.

 

[n0uy]

In my manual it states there is an electronic flasher cancelling unit. The time lapse is dependent on the speed of the machine. The faster the machine is traveling the quicker it cancels. It does not state if this is by rpm or actual mph. It says if the unit has failed it is normal to get about one flash or so then it cancels. I don't know if this helps you out or not.

 

[n0uy]

The only thing I can think of is a bad switch which also may be a part of my problem.I go to turn my signals on and the switch wont stay in place its keeps moving back to the off position.
Other than that you have loose connection to the ground wire somewhere within the relay for signals.

On my 1981 model the turn indicator switch goes back to center immediately but the indicator continues to flash until the auto cancel stops it, or you can push inward on the switch to cancel immediately.

 

[xschris]

The switch should go back to the center position. Just as n0uy says.

 

[84Seca]

It does go back to center like normal, but it then turns off before I push it down.

 

[Lou Ranger]

It does go back to center like normal, but it then turns off before I push it down.

If your auto cancel is like mine, it does not leave the flasher on for long enough - unless you wait until you are too close to the intersection to turn it on.
If I wanted flashing to start from a proper distance away from a turn and continue until I was through the turn, I would have to turn it on twice. There's no adjustment that I know of.

 

[BBS360]

It does not state if this is by rpm or actual mph. It says if the unit has failed it is normal to get about one flash or so then it cancels. I don't know if this helps you out or not.

The auto-cancellers are definitely not adjustable. They read signals directly from the speedometer. It's possible, but pretty unlikely, that the sensor in the speedometer housing could fail rather than the auto-canceller itself.
Apparently they fail with age. The only solution other than replacing it with another identical auto-canceller is to bypass it.
It's the most common solution.

I've fabricated a complete replacement with a modern microprocessor but there are still some kinks to iron out and my bike's not on the road.

 

[84Seca]

Any idea on where the sensor is or how to by pass it? I know there is a small fuse looking thing in the speedometer housing, could that be it? What I have been doing is starting the signals normally and then refreshing it once I get close to the corner.