Electrical problem : Help please

bluecorvin

bluecorvin

Member
:( 1981 virago 750.Bought a running bike , transformed it into an awsome cafe racer.Almost at the end of my project hooked everything up ,still waiting for the digital speedometer, but it will not start, not a click or nothing.Checked everything, ground , battery, Starting relay, starter , push button, fuses and still nothing .
What am I missing? Anyone? Please help if you can and thank you.

Alex 519-574-0517
 
If you hear nothing. I would consider checking your various safety interlocks. Clutch/Kickstand/Kill. Then if still nothing confirming the starter relay works would be next for me, generally I just measure if I get the coil energized when I press the starter button, then confirm that the relay closes. A more simple test is to use a screw driver to bridge the relay and see if the starter turns (BTW this is not a safe thing to do so do at your own risk) If it does than you are likely just trying to determine why you are not getting the coil energized or possible replacing the relay itself.

The clue for me is that it doesn't make any noises when you press the starter button. My guess either relay or relay coil is not getting energized.


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How did this end up in the Fallen Riders forum?
 
Another member was having trouble with his old bike and in that case there was a headlight interlock. Where do they come up with these things?

Do you have a wiring/block/circuit diagram for your bike to see what interlocks they used?
 
Thank you very much. I have done the relay coil trick already and bike turns over so the coil and starter motor is ok. I have to check why I`m not getting power to the relay when pushing the starter switch button.
Thank you again.
 
you need to get it to someone who can test out the wiring and systems. is the harness all stock ? or have you modified it?
 
Check the starter circuit cut out relay if you can. It could be upset or at the very least you can figure out if it is getting a kill signal from one of the sensors that thirstforspeed mentioned. If the problem isn't in the sensor side of the circuit, that puts you into engine start switch/starter relay/starter switch/main fuse to be investigated.

Whats the line between the tach and starter relay? Does it prevent engaging the relay when the bike is running? Did you remove the tach?
 
Thank you all. I worked at it all day and the problem is still there. Things that I have done include:
-replaced the starter switch and kill switch: no change
-Tested the starter - ok
-Tested the starter relay - ok
-Tested Battery -ok
-Tested clutch interlock -ok
- Tested Starting relay -ok
-Tested neutral gear interlock -ok
Tested all relays -ok
Noticed the headlight is not coming on either
-Tested all fuses -ok
Everything else , Horns ; signal lights; stop light ok
I was told that the old Viragos could be a hand full and I did not believe it , I know better now.I will get it but it will take some time.

Thank you all for your input .
 
is the hand control plugged into the loom? are there broken pins in the plug in the headlight bucket plug?

alternatively, is the plug for the keyswitch fully seated?

i know these bikes pretty well. usually its something really simple that is not working perfectly, not a major component failure of some sort
 
Are there signs of life when you turn on the key? If not, my vote is for ignition switch not powering up the fuse box.

PS: Thanks to thirstforspeed for posting the wiring diagram. It makes things much easier.
 
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You have your bike's electrical schematic. All you need is a multimeter. Go through the electrical schematic, from the battery's +, following every wire, connection, switch, fuse and use your multimeter to check for electrical connectivity. When a section of the electrical schematic has been checked, cross it off and move to the next. Be methodical and you will eventually find the culprit. All electrical problems are this way. You need to use a multimeter for all checks, as visual ones are not sufficient.

For a new sued bike I always go through wire by wire, connection by connection and check everything. This is time well spent and will pay you back with reliability.
 
I have got it running today.I want to thank you all for all your input as I always told everyone else all my life , there is nobody else better then bike people. Ok I know everyone wants to know WHAT WAS WRONG.
After checking and testing everything I hot wired it today to bypass the main start switch and it worked.Then I realised that the only reason why this is not working is because on the right hand switch which holds the push button and the kill switch I have a 4 wire plug that plugs in a 3 wire plug on the main harness ?????? I am not kidding you , and the black wire(ground wire) was not plugging into nothing so I ran a wire to the ground and BINGO it is fine now.
Still a mistery to me is why was it working before I took it apart? I am going to sleep a happy man tonight.

Thank you again and I will posting some pics of the finished bike when that happens.

 
If you examine the schematic that was posted, the right hand controls are supposed to have a 4-pin plug mate to a 3-pin receptacle. It looks from that diagram that the engine start switch is supposed to be hanging in mid air. That is strange that it all worked before you took it apart.
 
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Right, but if you look at the function of the circuit, pressing the starting button (if the circuit is as per the diagram) leads to a circuit that goes nowhere.

On the other hand, if you hypothetically pull the blue-with-white-stripe wire to ground, it grounds one side of the main starting motor relay. The other side of that relay (red with white stripe) comes from the "starter relay", whose internal function is not discernible from the diagram, but other wiring involving that relay and the one next to it is coming from power from the ignition switch, the side stand switch, the clutch switch, the neutral switch, etc.

Obviously the missing pin needs to be grounded, as the original poster has found out. There is a fair chance that the stock design of that switch housing internally grounds that circuit, and something that was done in the process of customizing that bike removed that circuit's path to ground.
 
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