Motorcycle Repair: Motorcycle electric, yamaha virago, worst case scenario

Question
Motorcycle Yamaha Virago 1985 700. My turn signals work intermittently. Sometimes they work fine other times they work but very slowly. My horns sound very low when this is occurring. My headlight and tail light blink when this is happening. Last year I put in a new battery. Bike starts and runs perfectly. I can find no ground shorts. When all is working horns blow signals work and the head and tail light do not blink.  All can work well when bike is running or just when I turn the key and bike is not running. Likewise if the bike is running at 2M RPM, very weird and unpredictable.

Answer
Hi Richard.

This sounds like you do have a number of shorts in your main harness.  My '86 XV700 had a similar problem.  Did you check for shorts with the bike running?  Did you use a multimeter to check or did you just look for obvious shorts (most guys just check visually, that's why I ask)?

I have seen similar problems and it is very likely that you have what is called an intermittent short and/or bad contacts in the switches. Start by checking and cleaning the contacts.

 Mostly, the shorts occur in the portion of the main harness that is at the steering head. Start by checking it this way;

1) place the bike on the centerstand with a strong fan blowing on the motor.

2) Start the bike.  It should idle at between 950rpm - 1050rpm, btw. If it is different from that, adjust it accordingly.

3) Turn the handlebars while you use the affected circuits and also grab the wires and move them around while using the affected systems. The shorts will make themselves known then.

 It is a lot of wires to check, but if they are there then you will have narrowed down the culprits.

Worst case scenario, you will have to take it to a shop for them to either replace the wiring harness or repair/bypass the damaged sections.

Let me know what you find.
Good luck and ride safe.
FALCON