A little electrical help???

[Skyguyz]

After I installed my engine I did a rough hook-up of the wiring for the whole bike. I got some good spark and all seemed good. The starter motor did not activate when the button was pushed and I noticed the 20 A fuse had blown, (this appears to have happened well before the starter button pushed. and subsequent blowing of the fuse had nothing to do with the start button.)
After a lot of detective work, whenever the yellow/green wire from the right handlebar start switch was hooked up the fuse would blow. I tested another right handlebar switch and the same thing, blown fuse. So ruling out the handle bar switch, I traced the yellow/green wire and it follows the wiring diagram exactly, (*The wiring harness is brand new.)

So, what is causing this to blow the fuse. I checked the whole wire and it is shielded from anything and not grounded out. I did a continuity test and it checks out fine, (*It only blows the fuse when the key is switched on of course.) The green/yellow wire as you can see in the diagram starts out at the starter switch goes directly to the starter relay. I unplugged the start switch coupling where it hooks up to the main harness inside the headlight and only connected the yellow/green wire and of course the fuse blew. The wires from the right handlebar switch do get warm before the fuse blows. It is grounding out some where but it I double checked the entire length of the wire and it is in good nic and does not touch anything but where it starts life inside the switch and where it ends at the starter relay.

Thoughts/ Opinions?


Sky

[Alan H]

Split the green/yellow at the connector near the starter solenoid and try the start button. If the fuse blows, it's back towards the switch, if it doesn't, it's the solenoid.
Right. Ignition on, and kill/run switch off. All ok? It's not the handlebar switch then.
Ignition on, kill switch on - leave the start button alone - does the wiring get warm? 
There are several other circuits in use now, generator rotor, regulator and ignition coils (orange wire from the kill switch). Does the fuse blow? You'll have to find the earth by pulling connectors to isolate parts of the circuit until the fuse doesn't blow. Favourite will be the connection at the rotor not having the insulator properly installed.

That should keep you occupied for a bit!
Please report back when there's more than two handfuls of freshly pulled out hair on the garage floor, when it's cured, or when you have some test results!!

[Skyguyz]

Split the green/yellow at the connector near the starter solenoid and try the start button. If the fuse blows, it's back towards the switch, if it doesn't, it's the solenoid.
Right. Ignition on, and kill/run switch off. All ok? It's not the handlebar switch then.
Ignition on, kill switch on - leave the start button alone - does the wiring get warm? 
There are several other circuits in use now, generator rotor, regulator and ignition coils (orange wire from the kill switch). Does the fuse blow? You'll have to find the earth by pulling connectors to isolate parts of the circuit until the fuse doesn't blow. Favourite will be the connection at the rotor not having the insulator properly installed.

That should keep you occupied for a bit!
Please report back when there's more than two handfuls of freshly pulled out hair on the garage floor, when it's cured, or when you have some test results!!

Alan, Thank you for the quick reply. The help here on this forum is invaluable. Thinking about it last night the main culprits are the starter solenoid or the rotor insulator. I will check them out today and hopefully, it will be an "Ah-ha" moment. The good news is that I have a new OEM main harness installed and I have two right handlebar switches which helps eliminated some guess work. I will press on.

If anyone else has suggestions, please chime in.


Cheers,


Sky

[Optedout]

I have little knowledge (particularly electrical issues) but my own experience this
year was the fuse blowing along with the rectifier burning out as a result of poor
earthing after powder coating frame. May not be relevant but may help you to
think from a different angle if you draw a blank after your planned checks.

[Skyguyz]

So here are the facts:

- the fuse will blow whenever:

1- the right handlebar switch is in "Run" position and right switch is connected to the loom AND the green wire that comes from the alternator is connected.

2-The fuse will not blow if the above conditions exists and the run switch is in the "Off" position OR the green wire from the alternator is disconnected.

*When the conditions in # 1 occur, the wires from the right handle bar switch get warm and fuse blows.

I have a new combo voltage regulator and rectifier. It dose not matter which I use, the old rectifier and voltage regulator or the new combo set. I have made sure the old rectifier
has a good "Earth" as well as when I hook up the combo, it's "Earth" is also good.

*I did bypass the green wire from the alternator to the coupling with a separate alligator clip test wire and it still blows the fuse. I checked the alternator where the green wire connects to the screw, (earth) and it looks solid.

*Alan said: "Favourite will be the connection at the rotor nor having the insulator properly installed." Is it the insulator that is around the 3 yellow wires in the pix below?

I disconnected the three orange coil wire and it still blows. I checked all the connections with an orange wire and they are all disconnected and not grounded to earth.

*I did change out the alternator connector with the 1 green wire and 3 yellow wires because the old one was cracked and ready to fail. When I redid the wires at that connector I know for sure the green wire matched up with the green wire that goes to the regulator. I assume the 3 yellow wires do not matter what order they are connect to in the connector?
*I did connect ONLY the green wire from the alternator to its connector and the the fuse still blew, no yellow wires connected; *(With the above conditions in #1.)

*I have two right hand switches and both are in very good nic as far as wires, etc.


So to summarize:

The fuse blows whenever the connector with the green wire, (1 green, 3 yellow wires connector) is hooked up from the alternator and the kill switch is in run, (Condition #1 above.)


???


Hummmm, Anyone?



Sky





My art work:

[Alan H]

Nothing to do with the 3 yellow (stator) wires. These go to the rectifier.
Disconnect the green wire from the rotor, then switch on the kill switch and ignition. Does the fuse blow?
The green wire should go to one of the carbon brushes that run on the tracks of the rotor. What does the rotor look like? Does it have a flat vertical face with 2 tracks on or does it have a 'nose' that sticks out with 2 tracks side by side horziontally?
Send me your email address and I'll send you a copy of a service manual with test data in.

[Alan H]

Also, here's one I wrote earlier!!

http://www.kettleclinic.co.uk/kcforum/v ... alternator

With info on both types of alternator and earth fault issues on the rotor.

I suppose we should have a wiring section and sticky things like this.

[Skyguyz]

The issue is resolved. A wrong way insulating washer was the problem. Many thanks to Alan for all the help. The powder coating is causing some earthing issues but those have been taken care of. Time to press on.

Sky



The plate on my 74 Norton:

[Alan H]

The issue is resolved. A wrong way insulating washer was the problem. Many thanks to Alan for all the help. The powder coating is causing some earthing issues but those have been taken care of. Time to press on.
Sky

Glad to hear the progress, pleasure to help.
That little washer has caused so much pain to so many people, similar fault as when the ignition points are fitted wrongly......
Regarding the combined reg/rectifier units, a mate recently had a problem with one which failed on the AC to DC bit, and a brand new one of mine didn’t work on the regulator bit, so we fitted an original rectifier and regulator and away she went again. Most of the time, it’s just a bad or dirty terminal that’s the issue.
I also did a ‘daisy chain’ earth wire from battery –ve to frame and to all the auxiliaries under the left side panel – solenoid, rectifier, regulator and indicator relay. Done in black wire with crimped connectors and heat shrink, it looks OEM and every little helps these old ladies. There'll be the same again on the 550J as the resto progresses to the electrickery bit.
I'll get some pics of it soon.