The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: R65North on November 21, 2016, 10:02:51 AM
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Hi All,
Had my '79 'Phase 1' R65 a few years now and am gradually changing bits and pieces as the years pass and time allows. My current focus is the front brake. My 79 bike has the early ATE caliper, specific to the R65 and also the optional twin disc setup. Originally it had the circular handlebar mounted MC but when that dies I replaced it with a new rectangular MC fitted to Phase 2, '81 onwards, Brembo-kitted bikes.
So, current brakes are adequate but wooden-feeling and retardation could be better. How do i improve the brakes most cost-effectively?
Options (there might be others!):
Replace original flexible hoses with some fresh
Change pads (current ones are newish and to original spec)
Replace ATE calipers with R65 Brembo calipers (if I can find a pair)
Replace OEM stainless discs with floating EBC items from Motorworks
Interested to hear from others who have upgraded from original spec ATE's.
I'd really like to keep the ATE calipers unless Brembo's offer a big improvement - but how could they given the seeming similarity of the designs?
Thanks for the opinions
Cheers
Dave
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I have Brembo calipers on my LS, I can't tell much difference between the ATE calipers on my '81 R65 .
I replaced the OEM stainless rotors, with EBC semi-floating steel rotors and EBC organic pads, no noticeable improvement in dry braking, but I saw a significant improvement in wet braking .
I also have braided stainless lines .
If you have the original OEM rubber lines, I don't know how they fare in your weather conditions, but they are probably at least 32 years old .
You're call on that .
With everything I've done, I have not seen any real improvement, other than wet braking and I live in a desert, so I don't get those conditions that often .
I replaced these parts, as they needed normal replacement, I personally would not go through the expense of replacing these parts, if they are still in good condition .
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Hi Bob,
Thanks for sharing your experience, it could save me a lot of time and money. Much appreciated.
Dave
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Nothing wrong with the Ate calipers except the spares are scarce and more expensive than Brembo.
I would look at reducing the master cylinder piston size to improve the master cylinder to caliper hydraulic ratio.
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Hi Barry,
Still got the R45 I see - I took full advantage pf your knowledge on the BMBIKES site a few years ago - many thanks!
Good suggestion about the MC, I will investigate that one.
Here's the bike last month BTW. '79 wearing 81 bodywork - I have the original but the later seat is lower and more comfortable IMO.
Cheers
Dave
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Hi Bob,
Just saw your point on the original hoses - yes, it's something I should replace, if bleeding the front wasn't such a chew I might've done it sooner...last time ended up pushing fluid up through the calipers with a syringe to get the air out.
Cheers
Dave
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Good looking bike !!!!! :)
I see you have ' gaiters ' on the front forks, I put them on my '81 and at first they looked real out of place, but after 10 years they look like they really belong there !!!! ;D
I kind of don't understand the problems with bleeding the brakes on an R65, I've used a vacuum bleeder for the last, going on 36 years without any issues .
Used it on my cars and bikes and quite satisfied with the results .
Only better method is pressure bleeding, but that's not really possible on a motorcycle brake system, I've tried and it's quite messy . ;D ;D ;D ;D
I just noticed that you're bike is a '79 model year bike, so the brake lines are 37-38 years old, I would not hesitate to replace them, if it were my bike !!!! :)
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So, current brakes are adequate but wooden-feeling
Here is a good page for master cylinder caliper ratios.
http://www.vintagebrake.com/mastercylinder.htm
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Hello,
When new my bike had a couple of ATE caliper and a 15 mm dia master cylinder. The feeling was spongy.
Then the MC leaked badly so Ibought a 16 mm dia MC. Feeling improved a bit.
I had one caliper with one piston rusted and this produced a "plop" when braking. At that time BMW had stopped selling pistons for the ATE. So I was forced to buy a couple of Brembos for the bike. Exactly same braking, "ploppingless" and purse empty.
In 2013 I exchanged the hoses for braided lines. The braking became excellent provided you had enough force to squeeze the lever.
If I had some money I would replace the MC by a 15 mm one...
Change your brake lines NOW.
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The table at vintage brakes doesn't include our 36mm piston size but it gives you an idea of recommended ratios in the range 23:1 to 27:1 for opposed piston calipers. It's not rocket science to work out the relative piston areas for our 36mm pistons and produce our own ratios.
A single disc Ate caliper with a 13mm master cylinder is 15:1 so quite some room for improvement.
The later single disc with bermbo caliper and a 12mm master cylinder is 18:1
A twin disc with 16mm master cylinder would be 20:1 which is better
And with a 15mm it would be 23:1 which is better still and probably what I'd aim for.
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Change your brake lines NOW.
You might tell your servants what to do but I'll change them if and when I choose thanks
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Thanks for the opinions Guys, I'm going to strip and rebuild the calipers with new hoses when I get around to it. Parts are expensive but available. The MC is a newish 15mm so will do just fine.
Cheers
Dave
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Change your brake lines NOW.
You might tell your servants what to do but I'll change them if and when I choose thanks
Your life, do as you please.
Too many reasons to die using a bike o add another one.
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Your life, do as you please.
Too many reasons to die using a bike o add another one.
It never ceases to astound me that people will turn a blind eye to very basic and immediate threats to their continued existence. I will put up with many things not being ideal on a motorcycle, except for brakes and tyres.
I have a particular view of the intelligence, or rather the lack thereof, of anyone prepared to gamble with either.
A 1979 R65 with original brake lines that are now 37 years old is quite simply a failure looking for somewhere to happen - no equivocation whatsoever.
Now I am also firmly of the belief that an adult should be allowed to do pretty much whatever they want to do providing they don't hurt others. Sadly, ridign a bike with dangerous brakes is somethign likely to hurt others besides yourself.
I recommend the OP sells the motorcycle and buys a revolver - there is a game he might like involving a revolver and one round in a random chamber.
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As Clint Eastwood so succinctly put it "Mans got to know his limitations". I happily rode my 1946 Triumph Speed Twin with nothing but a rear drum brake for years. Anything with a disc brake is such an advancement over the bikes of the past. Just got to know your limitations...
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I happily rode my 1946 Triumph Speed Twin with nothing but a rear drum brake for years.
Yebbut, you were never going to get fast enough on the second most misnamed motorcycle of all time to actually hurt yourself :) :) :) :) :) :) :) :) :) :) :) :)
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I think the concern about the original brake hose has been a little overdone. Has anyone actually heard of them failing ? I seem to remember a debate a little while ago about how they were constructed i.e are they just a multilayer rubber hose which you can imagine would eventually deteriorate or is there a more rigid nylon inner liner ? When I've tried to test a good rubber brake hose by measuring the outer diameter with a digital caliper while applying grossly high brake pressure I've seen zero measurable expansion. That suggested to me that they weren't just rubber.
If rubber brake hoses are visibly deteriorating they usually get replaced but it would be interesting to cut one in half to see if replacement was justified.
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A brake hose failure can happen at anytime regardless of the age the hose is. I have had one rupture that was 20 years old and one that was clapps and keeping th rear brakes applied. It was only 5 years of old. If you go by what must aircraft manufacturer recommend you should replace them from 5 to 10 years of age.
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I think the concern about the original brake hose has been a little overdone. Has anyone actually heard of them failing ? .
Rear brake hose on my R100RS ruptured in use - all my own work, it was the rear hose so I just let it slide and one day it simply let go.
Shortly after one of the flexible lines on our ancient VW kombi let go. I replace all flexible hoses every 5 to 6 years as a result.
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Yebbut, you were never going to get fast enough on the second most misnamed motorcycle of all time to actually hurt yourself
So now you have me wondering what the most misnamed motorcycle of all time is?
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Yebbut, you were never going to get fast enough on the second most misnamed motorcycle of all time to actually hurt yourself
So now you have me wondering what the most misnamed motorcycle of all time is?
Well its a toss up depending on just who you are trying to insult at the time I guess.
The range of possibles would include:-
Norton Dominator (Unless "domination" of your wallet and savings counts)
Anything made by DOT (An obscure brand so it needs to be explained that DOT stood for (D)evoid (O)f (T)rouble, which they certainly were not.
Others can enter their own, but these will do for a start.
P.S. I would love to have included Norton Electra in my list, having once had the misfortune of owning one (and yes it broke the crank) but I remain to this day uncertain as to whether this model was actaully intended to be a motorcycle, I suspect it was a clumsy attempt to create a mechanical dog!
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I've had two OEM brake line failures, my '81 R65 had a failure at 10 years of ownership, my oilhead at 11 years .
The R65, I found before I rode it, the oilhead line failed in heavy rush hour traffic at 65 mph, about 110 kph . :o
The lines on my '81 R65, were just rubber, no fabric reinforcement, or liner in the line, the oilhead line was about at best 2 mm thick hose, no reinforcement or liner .
My '87 Guzzi, the original owner bought it from the dealer in '91, one of the front lines failed in '97, he replaced them with braided stainless lines .
In my experience, I don't trust OEM rubber lines, when my cars are out of warranty, they get braided stainless lines !!! 8-)
But, in my situation, the incessant heat of the low deserts of south central Aridzona, is not kind to rubber and plastic components either, I live in one of the worst case scenarios for vehicles !!! :D
But, it is a ' dry ' heat !!!! ;D
And I tend to keep cars a bit longer than the usual person, I've got one going on 38 years, the next one, is 17 years .