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Old 03-08-2004, 11:24 PM   #1
deangs OP
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R80 G/S brakes upgrade?

What's the best way to upgrade the front brakes on an 81 R80 G/S? MAP Engineering no longer makes a bigger rotor and caliper adapter.

Do I have any options?
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Old 03-08-2004, 11:55 PM   #2
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Why not try a (used) 4-pot caliper off another bike? You'll need to make an adaptor plate & possibly two spacers to mount it. This is something I've a few times eg. ISR calipers on to a GSX-1100, 1100EFE calipers on to a GSX750E & GSX-R caliper on to a DR600.

You could fit an oversize disc but if fitted in conjunction with a 4-pot caliper, you could end up with a brake that's too fierce for off road riding & liable to lock up.

Mounting a different caliper requires some lateral thinking, a dose of common sense & basic power tools. Access to a lathe is very useful, for the spacers.

Steve
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Old 03-09-2004, 03:10 AM   #3
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You could always go for a cast iron didk, it will mess up the rim in wet weather but it does break harder
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Old 03-09-2004, 12:20 PM   #4
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Hmmmm.... great idea on the caliper thing. Does anyone know if 4 pot caliper from another bmw would bolt on? I'm not too handy with power tools and don't have a lathe. Maybe something off of a newer model?

The cast iron disk sounds the easiest, will a dealer have one or do I need to find one used? What bikes did these come off of?
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Old 03-09-2004, 12:41 PM   #5
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Cast iron discs tend to be from aftermarket suppliers - there's a good choice in the UK. You may get another BMW caliper that will bolt to the fork but I doubt if one will meet all mounting criteria.

Re: power tools: you can get by with a bench, vice, drill (preferably a pillar or bench drill), files & a good jig saw will save a lot of time.

Feel free to PM me for further advice. If you're not to good with the power tools, all you can is mess about with a few bits of sheet aluminium & keep practicing.

Steve
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Old 03-09-2004, 12:54 PM   #6
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R80 G/S Brake Upgrade

Dean,
Attached ( I hope ! ) is a pic of my R80 G/S PD with a modified front brake. Caliper is Brembo 4 piston from Ducati 906 Paso. Making the bracket was started with a cardboard template. Apart from the rear relief done with a pass on a mill, the work was done by hand with a die grinder and files. You do need to have a new brake line made.
It is possible too, adapting the 4 piston Brembo from the R1100 & 1150 or the late K series for use in this situation. These are usually reasonably priced.
The total setup is actually lighter ( less unsprung weight ) than the original, though only by a few grams. Brake is now more progressive ( good for gravel roads ), with enough bite to have the front tyre squeeling if necessary. Master cylinder not changed. If a larger master cylinder were used, brake would have a harder feel initially at the bar.
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Old 03-09-2004, 12:57 PM   #7
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Try this pic, I think the pic I wante to attach was too large.
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Old 03-09-2004, 01:07 PM   #8
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I'm sure there are several Brembo calipers that could be adapted to the G/S. You'll have to match up the mounting holes, the alignment with the disc, and the master cylinder diameter. You'll also have to make sure the inside of the caliper clears the spokes.

Now, remember I've only piloted a G/S a few hundred miles...I certainly was not overwhelmed by the stopping power. It did seem to me, though, that the front brake was nevertheless capable of overwhelming the front tire--and the front forks. Better forks will transfer more weight more securely to the front, and improve braking. I've found that Galfer Green pads work extremely well, giving much more feel if not more absolute power. You might also consider a different master cylinder. The no-name on my KLR is a much better piece of equipment than the Magura on my old GS ever was.

I always found airhead drum rear brakes to be near worthless. Judging from the results my pal obtained with his R69, it might be worth a chat with Michael Morse at Vintage Brake in Sonora to see what he could do.

I guess my real point here is that there are many ways to make the old beast stop better, feel better.
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Old 03-10-2004, 11:22 AM   #9
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All you need to do to upgrade the brakes is get a stainless steel brakeline from Galfer. The difference is AMAZING. The stock line is made from old rubberbands or something.
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Old 03-10-2004, 03:33 PM   #10
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I concur with the Flasher. I just added a stainless line to my stock R65 Monolever single-disc setup, and it will howl the front tire if necessary.

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Old 03-10-2004, 04:10 PM   #11
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Hey now I think I can handle that. I'll get a stainless line first, if I still need brakes I'll try the caliper fitment suggested by others.

Thanks to all for the help!

Dean
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Old 03-10-2004, 04:11 PM   #12
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While I'm looking at it.... Hey Jackafrica, wanna sell your brake set up steel lines, caliper, caliper holder and rotor?
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Old 03-12-2004, 12:25 PM   #13
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G'day Dean,
What..........and go back to the shit original, sorry, no way jose ! I'm sure the later gold coloured 4 piston Brembos could be had for little money. They rip 'em off Dukes ( 748, 916,996,ST2,monster, etc. ) and sell 'em cheap on ebay. One of these could be adapted to the G/S, I'm certain. You're in the box seat there in the USA for those purchases.
If you go that route, there are two different mount spacing widths to consider. check out bikes in the dealerships, or on the street to gauge which might be best suited. Clearance of the spokes and angle of caliper relative to position for full brake pad coverage being the main points. A bike wrecker too would likely have a wide choice of Japanese calipers to choose.
My apologies for the late reply.
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Old 03-12-2004, 01:03 PM   #14
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Steve Allen at BevelHeaven is a Brembo dealer and, what's important here, knows all the dimensions. He is, obviously, focused on good ol' bevel Ducatis so he mostly stocks the F08's--the two-pots rather than fours--but he's a good feller and has messed up..er...with a lot of different kinds of bikes. Not cheap, but competitive prices.
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Old 03-12-2004, 02:35 PM   #15
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Comparing the R1100GS calipers with the space available on the G/S, the Brembos from the Ducatis and like will be a little easier to work ( due to mounting centre width ), but the BMW brembos are not out of the frame either. Clearance is not a problem for either type.
Personally, I prefer the generic Brembo set up as there is a wide range of pads and materials available.
Hope this helps rahter than confuses.
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