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Old 04-08-2013, 11:39 AM   #1
hobbsic OP
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Cry Did I do something stupid?

Well hello there!
Long time lurker who spontaneously bought a 1974 R74/6 last fall. I'm really just working my way through the, I guess, normal steps of bringing a sleeping beauty back on the road. Anyhow. After rebuilding the forks I moved over to the leaking master cylinder under the tank. Not a pretty sight. Anyhow, after search the interwebs for general information about that, I stumbled upon the "switching to handlebar mounted MC"-solution!

I bought an old throttle assembly, bad in all the right places, and cut it up. Well, in the middle of that process I stepped back, thinking, of life's inner meaning and my latest.. uhm, mistake? The throttle part of the sliced one is shorter than the one original on the bike. I guess it won't be able to pull the throttle cable as far as the original would..? Am i screwed?

Them things:


That bike:


So, whaddya say, is it a ?
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Old 04-08-2013, 01:45 PM   #2
Plaka
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Quote:
Originally Posted by hobbsic View Post
Well hello there!
Long time lurker who spontaneously bought a 1974 R74/6 last fall. I'm really just working my way through the, I guess, normal steps of bringing a sleeping beauty back on the road. Anyhow. After rebuilding the forks I moved over to the leaking master cylinder under the tank. Not a pretty sight. Anyhow, after search the interwebs for general information about that, I stumbled upon the "switching to handlebar mounted MC"-solution!

I bought an old throttle assembly, bad in all the right places, and cut it up. Well, in the middle of that process I stepped back, thinking, of life's inner meaning and my latest.. uhm, mistake? The throttle part of the sliced one is shorter than the one original on the bike. I guess it won't be able to pull the throttle cable as far as the original would..? Am i screwed?

Them things:


That bike:


So, whaddya say, is it a ?
I'd say the picture is utterly confusing. What do you have? What are you cutting up and why?
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Old 04-08-2013, 02:04 PM   #3
elite-less
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Can't say I've ever seen a throttle cam with a shorter arm like that. You'll need to remove the tops and compare/measure the inner cable channels.



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elite-less screwed with this post 04-08-2013 at 02:16 PM
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Old 04-08-2013, 02:20 PM   #4
hobbsic OP
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Originally Posted by elite-less View Post
Can't say I've ever seen a throttle cam with a shorter arm like that. You'll need to remove the tops and compare/measure the inner cable channels.



.
Hmm, yeah, I did, and it's like 1cm shorter than stock. Maybe it's not even a BMW part from the beginning?


Plaka:
Heres a link for you!
http://forum.boxerworks.com/viewtopic.php?f=1&t=5461
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Old 04-08-2013, 02:50 PM   #5
Mista Vern
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Quote:
Originally Posted by Plaka View Post
I'd say the picture is utterly confusing. What do you have? What are you cutting up and why?
What he said.


PS: What's in the boxes?
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Old 04-08-2013, 02:58 PM   #6
Plaka
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BTW, from what I can see, that's a special tank. Get it off the petcocks.
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Old 04-08-2013, 03:11 PM   #7
tradern
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Lever broken off the tip?
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Old 04-08-2013, 03:22 PM   #8
ericrat
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Looks like a generic aftermarket Magura master cylinder and a BMW throttle assemply with the brake cable portion "sliced" off.

No point in worrying about it too much now that the deed is done. ASSUMING you have the carbs and throttle cables, wire it up and make sure the butterflies open all the way to the stops, it should be obvious enough. Note that cams inside the throttle assembly are not all the same. You may wan to use the cam out of your original throttle assembly.

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Old 04-08-2013, 03:55 PM   #9
Plaka
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Quote:
Originally Posted by hobbsic View Post
Hmm, yeah, I did, and it's like 1cm shorter than stock. Maybe it's not even a BMW part from the beginning?


Plaka:
Heres a link for you!
http://forum.boxerworks.com/viewtopic.php?f=1&t=5461
Gotcha. Thanks!

I really like the paint on the tank in the pic (at the link). Wonder what it is?
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Old 04-08-2013, 04:00 PM   #10
danedg
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That would be a 1974 R75/6.....

The shorter cap probably won't work. But you should be able to switch caps to "stretch" the cable correctly.
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Old 04-08-2013, 04:35 PM   #11
garthg
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Tank Stand

Quote:
Originally Posted by Plaka View Post
BTW, from what I can see, that's a special tank. Get it off the petcocks.
On that point, Chris Harris mentions, but doesn't show, a tank stand he built to hold tanks off the bike.

Does anyone know what this looks like?
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Old 04-08-2013, 06:02 PM   #12
Brun
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Quote:
Originally Posted by hobbsic View Post
...The throttle part of the sliced one is shorter than the one original on the bike. I guess it won't be able to pull the throttle cable as far as the original would..? Am i screwed?
G'day Hobbsic. I'm responsible for that Boxerworks 'how to', and am still delighted with my front brake. I'm wondering why you used a replacement throttle housing - which I think comes from a R60/5 - rather than the one you had. I'm sure you can get or make throttle cables to suit the new one, and it is probable that there would be less throttle movement, but I would be more concerned about getting a smooth throttle operation.

When these things get old they get very lumpy. My suggestion would be to test both by assembling them on the handlebar (with cables) and test the feel while applying tension to the cables. You can also measure cable travel at the same time. Go with the smoothest operating one. I replaced the twisty part and the gear and chain part on mine with new parts. This greatly improved things but the wear in the housing is still causing lumpiness, though it's acceptable to me.

You will love the new brake. Good luck with it.
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Old 04-08-2013, 06:11 PM   #13
Plaka
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Quote:
Originally Posted by Brun View Post
G'day Hobbsic. I'm responsible for that Boxerworks 'how to', and am still delighted with my front brake. I'm wondering why you used a replacement throttle housing - which I think comes from a R60/5 - rather than the one you had. I'm sure you can get or make throttle cables to suit the new one, and it is probable that there would be less throttle movement, but I would be more concerned about getting a smooth throttle operation.

When these things get old they get very lumpy. My suggestion would be to test both by assembling them on the handlebar (with cables) and test the feel while applying tension to the cables. You can also measure cable travel at the same time. Go with the smoothest operating one. I replaced the twisty part and the gear and chain part on mine with new parts. This greatly improved things but the wear in the housing is still causing lumpiness, though it's acceptable to me.

You will love the new brake. Good luck with it.
What kid of paint did you use on that project? (the tank)
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Old 04-08-2013, 06:12 PM   #14
Plaka
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Quote:
Originally Posted by garthg View Post
On that point, Chris Harris mentions, but doesn't show, a tank stand he built to hold tanks off the bike.

Does anyone know what this looks like?
A coupla two by fours?
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Old 04-08-2013, 06:24 PM   #15
Brun
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Quote:
Originally Posted by Plaka View Post
I really like the paint on the tank in the pic (at the link). Wonder what it is?
You mean this?



It's matte black Wattyl Killrust Epoxy Enamel, from a rattle can. Not sure if Killrust is available elsewhere than Australia. I baked it by my woodstove between coats, and it is wearing well. Here is the rest of the bike.

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