wiring guru needed

[chaz46]

On my BSA A50 import from America, its running Boyer ignition and 12v battery but no ignition switch only two rocker switches. one presumably the ignition on /off and the other headlights.
Ive never come across this sort of wiring before. from the diagram I would like to know a few things.
1/. both high and low beam are joined into relay 1, will the relay dip the bulb?
2/. are both 20amp fuses needed in line?
3/. probably need a horn and rear brake switch, where is the best place to feed from?
4/. 2 relays? are they both needed?


going to rewire but there are brackets fitted and the frame has been powder coated as is. just looking to replace old wire for new.
thanks..

[BBROWN1664]

can you upload the diagram in a normal format? I cant open it.

[unfazed]

Double check you wiring as the diagram appears incorrect for the operation of the relays.

Relay will  just switch power to the lights and your diagram has the high and low beams on together. You will need a change over switch for the lights to switch from low to high. A change over switch will take 3 wires. In your drawing the Blk/Yell will go to the center pole of the switch and the  Blue and White will go to the outer 2poles.

[BBROWN1664]

Double check you wiring as the diagram appears incorrect for the operation of the relays.

Relay will  just switch power to the lights and your diagram has the high and low beams on together. You will need a change over switch for the lights to switch from low to high. A change over switch will take 3 wires. In your drawing the Blk/Yell will go to the center pole of the switch and the  Blue and White will go to the outer 2poles.

On older vehicles it was common for dipped to remain on when high beam came on so it may not be incorrect.

[unfazed]

Any BSAs I've rewired had dual filament bulbs. The charging systems didn't have enough power to light two bulbs at the same time. It struggled with one. The days of candles in brown bottles is what we referred to them as 

[chaz46]

its  a strange one, Ive not touched the wires or the way its been wired to relays since it was on the road in America.
Im lost with relays, Harley Ironhead ones are just as dodgy except they go and reset themselves if they over peak.

[unfazed]

Where did you get the diagram? What year is the bike?

[chaz46]

I drew the diagram, from the wiring in the bike. 1969.

[unfazed]

Ok. obviously rewired with minimal wiring. Look at the underside of the relays and put the numbers to the relevant wires on your diagram and I will show you how it works on your diagram

Attached is a picture of the two most common relays you will get at the Motor Factors with the inner workings shown

[chaz46]

sorry for the delay, got a new puppy and looking after her.
both are the the 5 pin relays 12v 30/40A
Ive updated the drawing with numbers, the middle pins are not used

[unfazed]

Was this bike running when you got it ????

I presume it is a positive earth set up and the red wire is the positive, but you battery show no wire to earth the battery which means there is no way anything on this will work as there is no connection between the battery and regulator which means it would never charge the battery or power the ignition box as there is no circuit. I would think there should be a connection between the two 20 amp fuses to the negative of the battery which I believe the brown wire to be.

The right switch appears to be switching the earth to operate operate relay one. This is turning on the power for the ignition and switching the earth to power up relay 2.The fuse on relay 2 is in the wrong side of the relay
There is so much wrong here I would think your safest route is to have the unit rewired properly and switch it over to negative earth. It is very easy to do on Alternator powered bikes.

Judging by the diagram the person got positive and negative earth mixed up half way through his rewiring job.

On older bikes the power line is  always switched not the earth as the risk of shorting out positive and negative is to high. 
The newer ECU drive bikes and cars switch an earth to power up circuits controlled by the ECUs.
I have seen many blow ECUs over this when they did not realise it.
I live in the south of Ireland and unless you live in Ireland I cannot help you to rewire it.

[chaz46]

thanks for looking,
I bought the bike and yes, temptation got the better of me. a squirt of easy start and a battery and it did start when I sussed out which position to have the switches in.
The wiring has not been changed since.
I will probably look into re wiring it neg earth and fitting in a key switch for security. which will mean Ive got to make new brackets, which Im also going to have to do to fit a screw on oil filter as well.

[unfazed]

If it was running then you missed something on drawing out the diagram.

The alternator has no connection to earth and the only way it knows if it is positive or negative earth is by which side of the battery is connected to the frame.
Since it is only lights and ignition it is fairly simple as lights, your relays work either way, (unless they have and internal diode but it would be written on it) and a horn with two connection. but you will have to ensure the Ignition unit is connected the correct way round.
You don't really need relays for the setup you require, just an ignition switch to turn on the power a switch to turn on the lights. a two way switch for lights,  a button for the horn and a rear brake light switch.  3 fuses should do, the lights the ignition and a battery fuse. Depending on how you wire in an ammeter if it has one and where you take the power from for the lights you may need a fuse between it and the regulator for safety

You can buy and old style two way switch with a horn button incorporated in it

[chaz46]

thanks for looking,
Im going to look into it as more fabrication needed. trying to keep it minimal and keeping the switches off of the bars.