Problems with rectifier/regulator

[DevonDel]

I'm in the difficult position of taking on someone else's unfinished project and I have an issue with the electrics.

I am using this wiring layout see picture.

The bike runs fine if I miss out the positive connections to the regulator/rectifier (clearly it doesn't change like that) but as soon as I connect the system up as shown the 20 amp fuse from the constant positive blows.

Why would that fuse blow?

Is there a way to test the reg/rec?

Could a faulty reg/rec cause this or something else?

Any help greatly appreciated.

 

[retiredgentleman]

I'm in the difficult position of taking on someone else's unfinished project and I have an issue with the electrics.

I am using this wiring layout see picture.

The bike runs fine if I miss out the positive connections to the regulator/rectifier (clearly it doesn't change like that) but as soon as I connect the system up as shown the 20 amp fuse from the constant positive blows.

Why would that fuse blow?

Is there a way to test the reg/rec?

Could a faulty reg/rec cause this or something else?

Any help greatly appreciated.

Yes, its likely a shorted out diode(s) in the rectifier section of the rec/reg. Page 158 of the Haynes manual shows how to test the rectifier. This question has been answered many times on this site, so use the Google Custom Search in the upper left corner to find those threads.