74 R90 – bar mounted master cylinder – how to

Discuss all things 1970 & later Airheads right here.
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Airbear
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Location: Oz, lower right hand side, in a bit, just over the lumpy part.

Re: 74 R90 – bar mounted master cylinder – how to

Post by Airbear »

Jean wrote:Airbear, HOW did you fasten the extensions into your handlebars? Are they an interference fit...epoxy, or what?
Both, Jean. An interference fit with a smear of green Loctite (638, I think). Epoxy would have worked, too.
I like having that bit of extra leverage for parking manoeuvres. Seeing less elbow in the mirrors is a bonus.
Charlie
and Brunhilde - 1974 R90/6
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Graduate, Wallace and Gromit School of Engineering and Design (Pending)
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Steve in Golden
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Re: 74 R90 – bar mounted master cylinder – how to

Post by Steve in Golden »

Brunhilde is sure looking classy these days Charlie.

Photos! We need more photos!
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Airbear
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Location: Oz, lower right hand side, in a bit, just over the lumpy part.

Re: 74 R90 – bar mounted master cylinder – how to

Post by Airbear »

Thanks all. I'm putting together an update on the Brunhilde refurb.
I wanted this thread separate and easy to find for others afflicted with the under tank thing.
I love this brake. Have I said that?
Charlie
and Brunhilde - 1974 R90/6
Image

Graduate, Wallace and Gromit School of Engineering and Design (Pending)
moosehead
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Re: 74 R90 – bar mounted master cylinder – how to

Post by moosehead »

Very nice Charlie.

Did you just run an ss brake line from MC to the ATE?....oops, read your post again and I see you did!

Looking to upgrade a single disc ATE arrangement on a project and this is the way to go! The undertank MC is shot so can eliminate that nasty arrangement in the process. Clever.

Oh boy, Bruny has new life :D
Retired from work....not life!
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Zombie Master
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Re: 74 R90 – bar mounted master cylinder – how to

Post by Zombie Master »

He's not just a pretty face!
Any and all disclaimers may apply
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Airbear
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Location: Oz, lower right hand side, in a bit, just over the lumpy part.

Re: 74 R90 – bar mounted master cylinder – how to

Post by Airbear »

Zombie Master wrote:He's not just a pretty face!
Too kind, ZM.
Charlie
and Brunhilde - 1974 R90/6
Image

Graduate, Wallace and Gromit School of Engineering and Design (Pending)
ray52
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Re: 74 R90 – bar mounted master cylinder – how to

Post by ray52 »

Airbear
I really like your magura conversion. I have a 1980 r100t.Would the 13 mm cylinder work ok with my dual disc ?This is my first BMW . I like the bike but the brakes suck.Am I going to have to use \5 switch gear?
Thanks
Ray
SamH
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Location: Tas, Australia

Re: 74 R90 – bar mounted master cylinder – how to

Post by SamH »

I converted my old 90/6 to twin disc with bar MC just before I sold it. I never did get it bled properly, could still pull the lever to the bar. I used a 1/2" master cylinder from memory. I don't remember all the details but I think 12mm was suggested for dual discs. 1/2" was the closest I could find.
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Airbear
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Re: 74 R90 – bar mounted master cylinder – how to

Post by Airbear »

ray52 wrote:Airbear
I really like your magura conversion. I have a 1980 r100t.Would the 13 mm cylinder work ok with my dual disc ?This is my first BMW . I like the bike but the brakes suck.Am I going to have to use \5 switch gear?
Thanks
Ray
Hullo Ray. Sorry, I can't help with first hand experience with either of those questions. I have heard that some have had success with a 13mm MC on twin discs, but maybe not with this particular MC. There is a thread on ADVrider that may be useful re this and the switchgear query. http://www.advrider.com/forums/showthread.php?t=742109

Ah, just had a quick flick through that thread and it appears that the later switchgear is problematic. Perhaps you would be better getting a later model stock handlebar mounted MC. Good luck with it.
Charlie
and Brunhilde - 1974 R90/6
Image

Graduate, Wallace and Gromit School of Engineering and Design (Pending)
kutter
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Location: Central Queensland, Australia

Re: 74 R90 – bar mounted master cylinder – how to

Post by kutter »

My 1985 R80 has twin discs on the front end
and a 13mm MC (Standard) on the handlebars.
Have just done a complete rebuild of MC
and brake calipers. Not easy to bleed but can be
done. Took several attempts from the top and
two injections from the disc end before I had good
feel and brakes.
3/85 R80 Mono
5/81 R100RS - Shed Find

kutter
Rockhampton
Queensland
Australia
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