BMW R75/5 wiring

Striker · Apr 8, 2018

I’ve just picked up a R75/5 in need of some work. It’s a none runner but most of it is sound apart from the wiring.
The wiring diagram looks straight forward enough so I’m thinking of making up my own loom and adding some fuses but Motorworks do a loom for about £75. Anybody any advise on which way to go on this? whilst I’m at it, is it worth updating/changing the rectifier and regulator at the same time? And if so with what?

Cheers Striker

mikeyboy · Apr 8, 2018

I normally fit an eletrex RR 45 on project builds,simplifies the wiring and normally improves the charging,
That said,if I was restoring a 75/5 I’d keep it as standard as poss ,and fit a new loom if one is available.
I’d replace the points ign with a Siemens electronic set up and leave it at that,
The older bikes are appreciating in value and a future buyer won’t thank you much if it’s fuckedaboutwith.

squibb34 · Apr 8, 2018

Having made up looms from scratch a few times, I would simply opt to fork out the £75 given the option. It's difficult to match the 'look' of new OE if that matters in your resto.

Making looms can be a time consuming process, particularly if you seek to match OE colour coding, However, resurecting the original can be the low cost option - damage is usually around the headstock or in a few exposed areas.

Striker · Apr 8, 2018

Thanks for the prompt replies

I’ll go with the new loom, it already has a Boyer ignition system on it. I don’t know how good or bad they are. I looked at the Siemens system On Mike’s recommendation, but it did not cover my bike, 1972.

I do agree about trying to keep it as standard as possible, but I don’t plan on selling it so would like to go for reliability over originality so please keep the advise coming :thumb2

Cheers Striker

mikeyboy · Apr 8, 2018

I fitted the Siemens system to the same bike this week,but if you already have an upgrade its a moot point

Beemerboff · Apr 11, 2018

I fitted a Boyer to my R75/7 around 20 years ago and it has been fit and forget.
Have a look at what EME have, they have wiring harnesses and a low cost reg / rec complete with the required loom.
And a few other goodies at sensible prices

Just replaced all the wiring ,etc, on my G/S and if the R75 is similar there are around 20 pieces of wiring required , so the main loom is only the start!
The Boyer and if you do it a revised reg / reg replace a few pieces which reduces the apparent cost of the change.
I run the Boyer through a separate fused relay - back then the Boyers were reputed to be voltage sensitive , yours might be a old one too.

airhead_eire · Apr 12, 2018

I have a Boyer Bransden in my '73 R60/5. I have found it to be reliable and problem free.

Beemerboff · Apr 12, 2018

http://www.euromotoelectrics.com/category-s/2179.htm

BMW R75/5 wiring

Striker

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squibb34

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Striker

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mikeyboy

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airhead_eire

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