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Helicon
| | Posted on Sunday, January 06, 2008 - 08:52 pm: | 
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I'd also have to say that the rear brake on my 1125R is fairly weak ... I'm hoping that it is just a matter of breaking in the pads. I might also try adjusting the brake level back a bit so that I am sure that my foot is not hitting the engine case. Other than that, the bike is amazing! Oh, and when it comes to a motorcycle safety course they teach you to use both brakes at the same time, not just one or the other. If we only used one or the other than what would be the point of having front and rear brakes??? |
Interex2050
| | Posted on Sunday, January 06, 2008 - 10:43 pm: |
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Thanks for the advice, and the links...
I will definitely try to bed in the brakes in such a fashion...I hope its not too late.
I will make sure to post the results tomorrow.
Best,
Peter |
1324
| | Posted on Monday, January 07, 2008 - 12:19 pm: |
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Considering this seldom gets done in most vehicles, I think you're fine as long as you do it. Over the years I've experimented with bedding vs. not bedding on one of my vehicles, and the bedded brakes ALWAYS outlasted the non-bedded pads/rotors. Also seemed to be more resistant to warping and pulsating....no actual laboratory experiments, though. |
Interex2050
| | Posted on Tuesday, January 08, 2008 - 02:07 am: |
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Well...
The bedding did not go as well as I had hoped.
It turns out that my rear brake is not capable of bringing the bike close to a stop from 35ish within a span or roughly 1000ft...
So I was not really able to reach 5% of the original speed...
Did this several times, and in the end the brake was just scalding hot and was turning interesting colors.
Took it for a cool down run, did quite have enough time for another bedding run...
We shall see if there are any benefits tomorrow...
That brake just feels hard and slippery... As if the pads/rotor were made of glass.
P.S.
Its Kawasaki's fault... |
Blake
| | Posted on Tuesday, January 08, 2008 - 03:31 am: |
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The only thing I know of offhand that causes the issue you describe is oil on brake disk/pads.
A troubling scenario may seem plausible: Over-filled oil, oil out breather into intake, oil passes through engine and out with exhaust, oil gets onto rear brake.
But if there is no evidence of any oil misting anywhere around the brake, rear wheel, or swingarm, then oil is probably not the issue. |
Zac4mac
| | Posted on Tuesday, January 08, 2008 - 04:07 am: |
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Water, oil and gas fumes from the exhaust(hot - warm) on a cold disk condenses, then glazes from use?
Are we back to looking for "turnouts" to re-aim the exhaust off metal parts?
This bears further investigation.
I'll be watching mine.
Z |
Trojan
| | Posted on Tuesday, January 08, 2008 - 04:24 am: |
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Buells have always had notoriously bad rear brakes, regardless of model, ever since the S1.
I was also told by a dealer that this is deliberate, because the front brake is so good and Buell did not want people to hurt themselves (honestly!). Not only is this Bullsh*t but it also makes the rear brake illegal in some cases. On my last Ulysses I could rotate the wheel by hand even with someone standing on the rear brake pedal, and that was after bleeding, checking and fitting new aftermarket sintered pads (bedded in correctly). This would technically be an illegal bike in the UK even brand new, as it is law to have a functional rear brake fitted. As we converted ours for race use it never became an issue because Phil never used the rear brake anyway, but for road use it is unacceptable and there are lots of people riding around on bikes that are illegal and maybe dangerous.
I don't think that the exhaust theory is plausible, as the heat generated from braking would be enough to burn off any small deposits (if any) left from the exhaust, provided the brake is working well enough to generate heat that is. If water condensing on the disc is enough to negate the rear brake we'll be in trouble when it rains!
Most sportsbikes have better rear brakes than the Buells I have owned, even with similar calipers fitted, so I belioeve the problem lies at the master cylinder rather than the caliper/disc end. |
Zac4mac
| | Posted on Tuesday, January 08, 2008 - 10:05 am: |
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Matt, I'm not concerned with the water in the exhaust, I've put a lot more water on the bike just from splashback from the roads.
Any petroleum components from the exhaust are going to be concentrated from condensation.
Warm humid gas, hitting a VERY cold piece of steel.
It all condenses on the disk, then the wheel.
My rear wheel has a significant film of something kinda sticky, so I just wonder what's sticking to the disk.
Like I said, further investigation.
My Buell experience is limited, an 03 XB9R and now the 1125R.
Both had/have useful rear brakes, not that I use it a lot.
Heck I rode a Sporty for 4 years in San Diego with NO back brake, never missed it.
Bed 'em in and keep 'em clean.
Z |
1324
| | Posted on Tuesday, January 08, 2008 - 11:03 am: |
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It's too bad my bedding trick didn't fix the problem. Oh well, I was hopeful, but the problem does sound a little drastic (as bad as you guys are saying anyway).
The condensed exhaust is an interesting theory, but I certainly hope Buell would have shaken this problem out. Since this problem doesn't seem to occur on ALL 1125's, it leads me to believe that we've moved from the realm of engineering and science to coincidence. Heck, if this is the case, fuel quality can affect the situation. I wouldn't even venture to guess on what concentration of spent combustibles would do this, let alone which specific compounds to look for. We need a chemist...
My experiences though suggest that any petroleum product on a brake system will severely heat up and discolor. A simple experiment for those who are willing might be to clean the parts with brake cleaner and then road test with the rear brake. If you really want to do this and factor out the exhaust, try to test with running the engine as little as possible...maybe even roll it down a hill without power (just don't forget to use the front brake )
As was already mentioned, my next thought would be that the system pressure is too low to adequately brake. This will be more difficult to figure out though because most people don't have the parts to measure the pressure. Even if you did, you'd need to do some calcs and compare to known working examples. But as a ball park, you could just compare the measured pressure to the theoretical pressure delivered by a fully compressed master cylinder. If someone wants to take their nice new 1125r apart, we can measure to determine this, lol. Might be an interesting exercise to compare to other makes and models!
However, if low pressure is part of the problem, you can further eliminate variables by making sure the master cylinder is allowed to build full pressure. Is the lever adjusted such that you can fully actuate the piston? Is the master cylinder rod (or other components) binding or interfering with anything? Any leaks?
How about the pads? Are they seated correctly? Do they have excess clearance to the rotor when not in use? Do they fully seat when the brake is applied?
I'm sure this post probably didn't help anyone out now that I think through it, because I really reiterated some basic stuff...so sorry in advance. But, you need to be methodical when it comes to this. Luckily, brake systems are simple in theory. Your main tuning knobs are coefficients of friction of the pads and rotor, surface area, and system pressure.
I said it before, and I'll say it again: my Buell brake works, but does so much less than any bike I've ever ridden. Such was the case with absolutely every Buell I've ever ridden. I've left coincidence out of the equation a very long time ago. Unfortunately for you guys, it sounds like your brake works even less than in my experiences... |
Interex2050
| | Posted on Tuesday, January 08, 2008 - 04:55 pm: |
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1324,
Your trick does work... It just takes time (at least on my 1125R).
My braking distance has improved at least 50%, and it is much more capable of holding the bike at a stop. I was always afraid of overheating the brakes on this thing, but I guess that is not as important...
Thank you!
There is at most a 0.5mm gap between the pads and the disk when disengaged, and the gap closes effortlessly when the brake is applied.
The pedal travel is hindered by the system pressure alone (unless there is something out of place inside the master cylinder).
The rotor used to get covered in a sooty layer before I got the catalyzed muffler, but that does not appear to be an issue anymore.
In the morning the disk does get covered with moisture from the exhaust, but aside from that there is no oil or any other liquid on the disk/pads.
We shall see, I just did another bedding "treatment"... we shall see what happens.
One thing that I would like to mention, even though it is stopping better... there is still no feel to it. |
1324
| | Posted on Tuesday, January 08, 2008 - 05:23 pm: |
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Good to hear...that makes my day, actually (pathetic, I know). You should only have to bed once, but just remember that you need to think of pads and rotors as a matched set from now on. If you change pads, resurface and/or hone the rotor. Always clean well!
And wait, you have a catalyzed muffler? Is this part of your sun tax? I didn't know the CARB models had them... |
Blake
| | Posted on Tuesday, January 08, 2008 - 05:40 pm: |
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"On my last Ulysses I could rotate the wheel by hand even with someone standing on the rear brake pedal, and that was after bleeding, checking and fitting new aftermarket sintered pads (bedded in correctly)."
That defies my experience riding a Uly, where I had no trouble at all locking up the rear brake. I'm no lightweight. Frankly Matt, your experience makes no sense at all unless the rear disk or pads had oil on them. Rotating by hand? Are you kidding me!?
Buell rear brakes have always been less powerful than some seem to want, but my experience is that ALL Buell rear brakes are perfectly adequate for locking up the rear wheel anytime you like.
HTFU.
(Message edited by Blake on January 08, 2008) |
Chadhargis
| | Posted on Tuesday, January 08, 2008 - 08:08 pm: |
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I am an MSF instructor (RiderCoach) and yes, we do teach "use both brakes", but you have to understand that the MSF course is designed to teach BASIC skills to riders of all kinds of motorcycles.
It's very rare that you'll see a cruiser do a stoppie. I guess it's possible, but I've never seen it. Most of them have very skinny front tires and long wheelbases. This makes using a lot of front brake not a wise idea. There is a lot of braking power in a cruisers rear brake.
In my 5 years of teaching the course, I'd say about 80% of my students plan on buying a cruiser of some sort.
On a sportbike with powerful front brakes and short wheelbases, the front brake can and will lift the rear tire off the ground. What the hell good is a powerful rear brake going to do you if your rear tire isn't on the ground?
Do you know what happens when the rear tire gets a little crossed up and the rear brake locks? It's call a highside, and it's BAD, BAD, BAD.
I do quite a few track days, and I never touch the rear brake. Even on the street, I'm very judicious with it. I'll use it in slow speed situations and on slick surfaces, gravel, etc. Otherwise, it's front only for me. |
Rocketman
| | Posted on Tuesday, January 08, 2008 - 09:49 pm: |
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This makes using a lot of front brake not a wise idea.
Then it would be prudent to teach them to use it correctly. edited to say - not you personally if you gets my meaning
Put it another way. If you teach a rider to control a braking motorcycle with the front brake only, that rider will always develop better overall control of a motorcycle than one taught to use both brakes. Once the principles of braking control are mastered at the front, bringing the rear brake into the equation is something any rider will learn the benefits of with a better understanding of what a rear brake can bring to the party.
 anyone for a new thread?
Rocket
(Message edited by rocketman on January 08, 2008) |
Old_man
| | Posted on Tuesday, January 08, 2008 - 10:18 pm: |
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When I was a motorcycle mounted policeman in the 60s and early 70s we rode Harley Duo-Glides, foot clutch and hand shift.
No electric start - spark retard on the left handlebar grip.
The front brake was nearly useless. The main brake was the rear foot brake.
You used the front brake to hold the bike stopped when you put your right foot down to hold the bike up. You needed your left foot to operate the clutch.
I did use the front brake in tandem with the rear because I had my own motorcyles that were not Harleys.- But I think I was the only one who did rely on the front brake also. |
Spatten1
| | Posted on Wednesday, January 09, 2008 - 09:27 am: |
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Rear brake for gravel, loose stuff in turnouts, etc. Front may tuck very quickly in loose stuff, rear won't. |
Zac4mac
| | Posted on Wednesday, January 09, 2008 - 11:33 am: |
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I checked my rear brake and then played with it a bit yesterday.
I've got the adjustable foot, on the lever, all the way back.
Not that I've got a tiny foot, but I have less trouble with trying to push on the engine for back brake instead of the lever.
I noticed my front disk is discolored some, but not the rear.
So, I started pushing harder, later when I needed it.
Each time it got stronger. So, I'll finish bedding the rear and all should be OK.
I'm also not concerned about exhaust deposits after what I've seen on mine.
Nothing is affecting the brakes outside the brake system that I can see.
Zack |
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