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/6 upgrades

Posted: Sun Aug 19, 2012 2:33 pm
by oldbmwmc
I have a 74 R90/6 with a ton of miles. I have owned it for 35 or 36 years at this point so I guess you could say I really like it. I rode it naked for a bunch of years, moved on to an S fairing, then an RS fairing, then a Hannigan, now back to the S with Albert Bar end mirrors.. It is currently painted yellow, but started life painted red. In the interim years it was grey with black pinstripes. It also has Lester wheels, a harrow tank bag and corbin saddle.

But it is time for a few upgrades.

I just replaced my headlight bulb with a HID unit and ballast. Not only is the light brighter, but the new light puts less of a strain on the charging system. This is a nice improvement.

On to other things..

I want to replace the key switch in the headlight housing. The original units are difficult to find at a reasonable price, and I am now on my third or possibly 4th one. Anyone have a good alternative? I'm open for ideas.

I have always felt that BMW made a giant mistake when it eliminated the very clean looking /5 headlight. The instrument housing on the /6 /7 series is an eyesore. What were they thinking?

As the tack has not worked for a few years now and the speedo is on it's way out again I think it is time to look at some n digital alternatives. I have looked at a bunch of them, but I would like some opinions as to quality and durability.

Naturally if I replace the speedo and tack I need a place to mount the idiot lights. I'm thinking of mounting them in a work box attached to the mount where the speedo & tack are now located. I could put the ignition switch in there as well.

The Corbin seat has seen better days as well. I'm thinking of going back to something that is closer to stock, but a bit rounded on the sides and perhaps an inch lower. I also like the look of the /5 dual grab rails on the seat, so I would like to mount those as well. Anyone have a good source for seat-pans?

This will be one of my late fall / winter projects, so I am gathering ideas now.

Please feel free to make suggestions.

One other thing... I keep hitting the starter button on the tank bag when doing parking lot maneuvers before riding away. Is there an interlock or interrupt in the clutch lever to keep that from happening? I have had this problem for so long I no longer remember.


Thanks in advance for your input.

Re: /6 upgrades

Posted: Mon Aug 20, 2012 4:14 am
by Airbear
Welcome to the forum, Old.
I totally agree about the /6 headlight and instrument arrangement. I suspect that BMW were trying to get a hondayamazootie look. Why not find yourself a nice /5 bucket? I had been looking for one for years and eventually found a chinese copy of a russian copy of something like an early BMW bucket on eBay for $100. My instruments died too, so I fitted an Acewell 2853 digital instrument ($250 at the time). This I am mostly happy with but the LED idiot lights are invisible in sunlight, so I am about to fit some extra idiot lights into the bucket. This is how it looks at the moment (er, last week actually - I've just pulled it all apart)

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The really nice thing is that the bucket came with a car type ignition switch at the top front - turn the key one click for ignition on, then a good spring-loaded twist for the starter. Can use either hand to start. I love it to bits, and having a nice old-school headlight leading me around makes me grin. I fabricated some stainless steel 'ears' to mount the bucket - they need to be longer than the /6 ears because the /5 type bucket is a lot deeper. I then added a couple of LED spotlights to add to the night-time light show. The bucket I got was a reject, I think. It is somewhat asymmetrical, but so am I.

Re: /6 upgrades

Posted: Mon Aug 20, 2012 11:31 am
by oldbmwmc
I saw your headlight setup from an earlier post. It looks sweet, but I am sticking with the S fairing as I like that look as well.

I was putting dielectric grease on the connections for the charging system today and now I have an electrical system failure. No good deed goes unpunished...

Re: /6 upgrades

Posted: Mon Aug 20, 2012 10:35 pm
by oldbmwmc
Well I wiggled a couple of wires around on the starter relay then everything was fine again. As the relay is OEM I may just replace it. New plug wires too, yellow to match the paint...The charging voltage as read at the voltmeter in the fairing is now 13.3 volts, up mor than 1/2 a volt by putting in the HID headlight and cleaning up the charging system connectors. Not too shabby.

Re: /6 upgrades

Posted: Mon Aug 20, 2012 10:56 pm
by mattcfish

Re: /6 upgrades

Posted: Tue Aug 21, 2012 3:50 am
by Zombie Master
Whatever you do; do not lighten the flywheel. IMO you will loose the great feel of the R90 engine. I had one for 11years that I bought new. Should have kept it but BMW said there would be no more big boxers. Sort of like not invading Poland.

Re: /6 upgrades

Posted: Tue Aug 21, 2012 3:51 am
by Zombie Master
Airbear wrote:Welcome to the forum, Old.
I totally agree about the /6 headlight and instrument arrangement. I suspect that BMW were trying to get a hondayamazootie look. Why not find yourself a nice /5 bucket? I had been looking for one for years and eventually found a chinese copy of a russian copy of something like an early BMW bucket on eBay for $100. My instruments died too, so I fitted an Acewell 2853 digital instrument ($250 at the time). This I am mostly happy with but the LED idiot lights are invisible in sunlight, so I am about to fit some extra idiot lights into the bucket. This is how it looks at the moment (er, last week actually - I've just pulled it all apart)
That looks really great Bear!

Re: /6 upgrades

Posted: Tue Aug 21, 2012 11:02 am
by Jean
Airbear's mod would be wonderful on a /5 too.
THEN the starter switch wouldn't hit the tank bag for one thing.
I like the eyebrow on the ring, too. What part is that, part of the Chinese assembly?

Re: /6 upgrades

Posted: Tue Aug 21, 2012 5:00 pm
by Airbear
Zombie Master wrote:That looks really great Bear!
Thanks ZM. I now think of her as being a R90/5.8 or thereabouts.
Jean wrote:Airbear's mod would be wonderful on a /5 too.
THEN the starter switch wouldn't hit the tank bag for one thing.
I like the eyebrow on the ring, too. What part is that, part of the Chinese assembly?
Yes Jean, came with the assembly. It's kind of cute. I'm tempted to add eyelashes.
I'm still wondering how to utilise the starter button. Could be an extra horn, or (preferred) trigger a relay to toggle the high beam. Sometimes it is tricky to move one's left thumb just so to dip the beam when night riding.
It should be possible to get a starter switch from an old car. It would need to be pretty compact. VW perhaps.

Re: /6 upgrades

Posted: Tue Aug 21, 2012 5:55 pm
by Airbear
Back to the original query - Old, have you looked at the Acewell range? I bought a budget model, but there are these -

http://www.acewell.co.uk/Acewell%20Spee ... /index.htm

Along the way I stumbled upon a German made speedo / tach that was particularly elegant, but cost 400 Euros. Can't find it now.

re the matter of the starter engaging, the /6 did have the requirement to be in neutral with the clutch engaged. Here's the starter circuit.

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The diode in the back of the terminal board in the bucket is part of the circuit. I guess this feature has been disabled in yours. I disabled it in mine too - damned irritating when you are sideways on a slippery and steep track in the bush. Having the starter spitting teeth in a parking lot is a bit irritating too, of course.

BTW, I've drawn up coloured circuit maps for the 74 R90 that you might find useful. I can't attach here but if you shoot me a PM or email with your email address I'll attach PDF prints to a return email.

Instrument pod

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... and complete map in A3 size

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