BSA B25SS Battery connections

Here you can talk about all kind of TECH for the B50 B44 B25 And Other BSA unit Singles

Moderator: minetymenace

Post Reply
davidprice
>10
>10
Posts: 14
Joined: Wed Feb 22, 2012 9:12 pm
Location: Kent UK
Has thanked: 0
Been thanked: 1 time
Flag: Great Britain

BSA B25SS Battery connections

Post by davidprice » Sun Oct 13, 2019 2:18 pm

This may sound like a dumb question , but, electrics are not my strong point, other than the two red earth, ground, wires coming out of the wiring harness that connect to the + battery terminal, is there supposed to be a separate earth wire that earths the battery directly to some earth point on the frame. I am at the final stage of a 35 year rebuild < is that a record) Having bought the bike more or less complete in 1984 . I stripped it all down so long ago that I can not now remember if there was a separate earth wire or not. The schematic wiring diagram or parts book are of no help. The schematic only shows that the battery is + earthed and does not even show the other two earth wires running to the battery.

User avatar
minetymenace
Gerry1
Gerry1
Posts: 7430
Joined: Wed May 26, 2004 1:00 am
Location: On the edge of Salisbury Plain, England
Has thanked: 14 times
Been thanked: 50 times
Flag: England
Contact:

Re: BSA B25SS Battery connections

Post by minetymenace » Sun Oct 13, 2019 3:55 pm

You haven't said what bike it is, but one of the red wires (from memory) is attached to the frame in the electrics box...using earth return for the electrics was a conscious decision based on financial grounds, I would run extra earth wires to the headlamp, tail lamp and frame just for good measure, but a new loom should be fine for 15 or 20 years to come....
There is no evidence to support the notion that life is serious.
Abyssinian Wire-Haired Tripehounds Gnash.

davidprice
>10
>10
Posts: 14
Joined: Wed Feb 22, 2012 9:12 pm
Location: Kent UK
Has thanked: 0
Been thanked: 1 time
Flag: Great Britain

Re: BSA B25SS Battery connections

Post by davidprice » Sun Oct 13, 2019 8:23 pm

Hi Thank you for the reply. My bike is a 1971 BSA B25SS. From memory several of my other bikes have one heavy earth lead from the battery to the frame and one or two other smaller diameter wires like the rest of the loom also connecting to the battery earth terminal. It is this heavy earth wire that I am wondering if this bike should have. The wiring loom only saw 10 or 11 years of service and has been sat in my garage for the last 30 odd years , other than a couple of missing nipples , which I have soldered back on, it is in good usable condition. I have fitted a replacement Lucas head light shell with halogen bulb and no pilot light . The original shell had an earth terminal to the shell but the new head light does not have one but the light unit has two earth wires attached to the bulb holder , so can I connect these direct to the earth wire that originally went to the old shell.

User avatar
kommando
>1400
>1400
Posts: 1846
Joined: Mon May 24, 2004 8:41 pm
Location: Scotland
Has thanked: 1 time
Been thanked: 30 times
Flag: Ireland

Re: BSA B25SS Battery connections

Post by kommando » Mon Oct 14, 2019 8:34 am

The heavy earth is only needed for starter equipped bikes, a normal gauge earth wire to replace the greased headstock bearings and painted frame is advisable.

User avatar
minetymenace
Gerry1
Gerry1
Posts: 7430
Joined: Wed May 26, 2004 1:00 am
Location: On the edge of Salisbury Plain, England
Has thanked: 14 times
Been thanked: 50 times
Flag: England
Contact:

Re: BSA B25SS Battery connections

Post by minetymenace » Mon Oct 14, 2019 10:47 am

davidprice wrote:can I connect these direct to the earth wire that originally went to the old shell.
Yes. :lol: :ok
There is no evidence to support the notion that life is serious.
Abyssinian Wire-Haired Tripehounds Gnash.

Post Reply