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Discussion Starter #1
I have a 02 road king that has a front tire replaced and new braided brake lines installed due to a handlebar upgrade. Now i have one front rotor getting hot Looking for some help::confused:
 

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Just passing thru
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Welcome to the forum Grumpy. Who did the work? A shop or yourself? I would think the one getting hot is the one thats working? Maybe you have a few more details. Does the bike stop OK? Is there enough brake fluid? Were the brakes bled properly?
 

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Official Ass Tweaker
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The rotor getting hot is due to the brake pistons not retracting correctly. This is most often due to sticky pistons due to dirt or corrosion in there. Could also be the dust seal which also acts as a return spring. The bike's likely not old enough to have trashed the bores, so a rebuild kit (2 seals per pot, basically) should do it. Maybe new pistons if they are seriously pitted but usually it's the seals. Cheap and not at all hard to do. Couple or three hours at a dealer.

Could have been the dealer if some idiot popped a piston out during the tire change and then just forced it back in without doing it right, but you'll never prove it :D
 

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I'd consider this a life threatening situation, if you get the fluid hot enough to boil, there will be a sudden big pressure buildup, and the front wheel might lock up solid and dump you at speed.
 

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Yup, take it back in and complain.
 

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I'd consider this a life threatening situation, if you get the fluid hot enough to boil, there will be a sudden big pressure buildup, and the front wheel might lock up solid and dump you at speed.
I'd second that. Exactly that just happened to a very experienced rider on the Suzuki forum I belong to. He took a 150 yard test ride, and his front locked solid. For the first time in 40 years he wasn't wearing any gear. Made a real mess of his skin, though fortunately nothing broken.

It can happen to the best of us.
 

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Discussion Starter #8
I found that the forks and the axel were not set right. I took a 7/16 drill and set the clearance and that took care of the problem The rotor is running cool now Thanks for the help
 

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...the brake never gets hard enough to lock up...
You'll have to explain that to a couple of guys on the V-Rod forum

Dave/Hans, I thought at first this statement sounded a bit dogmatic. Then it occurred to me that you have riding experience a lot of us do not have, racing long enough and hard enough to over-heat the brakes. Prolly in that case, a pressure buildup from boiling brake fluid could not cause lockup, the pressure would just backwash into the brake master cylinder, as it does every time there is a release in pressure during normal use. The cases I had in mind were the result of a profound malfunction.... they had inadvertently installed what amounted to a check valve that prevented the return of pressure after a normal brake application, or the venting of the pressure increasing with heat...

Two or three different guys did have front wheel lockups, one at full speed on the highway, all three seemed to be from misfitting aftermarket handbrake levers. Theoretically, the binding lever kept the piston extended just a bit, enough to block the pressure relief orifice, which didn't let the fluid return to the brake master after front brake application, the brake fluid boiling did cause front brake lockup, and a fall, on a straight run down the highway.

Danno is the user who went down at speed, the archive seems to end and I can't fine the first post after his crash, only subsequent comments about it.
I haven’t had the time or the ability to thoroughly diagnose the cause of me and my pony going down but I have a pretty good idea what caused it. After seeing a post by CaptClose (Ryan) about his front brakes locking up, I put 2 and 2 together. After we compared notes, Ryan advised that he had a set of Kuryakyn Boss Blade levers installed and experienced his problem on the ride home from the dealer. Fortunately, his problem occurred at a stop light. I had installed the very same levers the morning of my ride but didn’t consider that such a low tech item could be the root cause of my accident.

After recently looking over my bike and examining the hand controls, I saw something that is confirming my suspicions and could have been an early indicator. The brake lever doesn’t appear to sit flush with the outer surface of the perch. This would indicate that the piston in the master cylinder may be partially compressed. This creates 2 problems. Pressure would be applied to the hydraulic system and the primary cup on the piston could block the pressure relief orifice in the bottom of the reservoir. I suspect the pressure caused the brake pads to drag on the rotors creating heat. The heat caused the hydraulic fluid to expand building pressure and creating more friction/heat continually feeding itself or perpetuating the problem. The primary cup blocking the orifice would hold the pressure in the line and not allow it to bleed back into the reservoir. They had to drag my bike off the freeway and it wouldn’t roll until the front brake system finally cooled down.

CaptClose
Danno, I am 99.999999% sure that the levers caused your crash. I was able to replicate my problem with the brakes several times without fail. My levers were installed by the dealer during my collision repair and passed the the post repair ride & inspection and was delivered to me unknowingly with this defect. If it wasn't for this forum, I would probably have been in a major accident. However, because of all the stories of dealers messing up bikes or forgetting critical fasteners, I took it very slow and cautious. I only live a few exits up from the dealership so I was luck to make it home safe.

Like Danno said, my brakes locked up at the stop light. When I punched the throttle, my front end just dove and I went nowhere. I couldn't figure out what the problem was but after a few minutes, the brakes cooled down and I was able to limp home.

Under the advice of the forum, I called the dealership and had them trailer my bike back. I spoke with the collision manager and he knew EXACTLY what the problem was. Because of that, I'm guessing this is a common problem with aftermarket levers.

They machined the levers and so far they have been trouble free. However, I still recommend genuine HD levers and would stay away from the aftermarket, especially the Boss Blades by Kuryakyn.
Max's comments to a naysayer...
Danno did not post this without a lot of thought and the first time I talked with him on the phone this item was suspect. I know of three reported cases of this already. I think Danno posting this is good for the community and if nothing else makes others aware of the possibility. Sometimes simple changes can have dramatic results.
I can't think of very many occasions where I might be inclined to call a lawyer, but this might be one of them...
 

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I hate necroposting for my first post, but this is the thread that lead me to my fix and I want to add my experience, as well as thank the posters here for the info provided.

I have a (new to me) '01 Heritage Springer with chrome HD controls. It recently sprung a leak from the outer seal of the front master cylinder. When I disassembled it I noted that the plastic cap that goes over the plunger had the tip broken off. It wasn't cut, it just looked broken. So I figured 'whatever, that's going to be fixed too'.

After rebuilding the master I had a heck of a time getting it to bleed properly. Then, once it was bled out, it kept slowly building pressure and dragging the brake, which perpetuated the drag. I tore that son of a gun down a few times, sure that I kept getting grit in the relief port in the master.

Then I read the post by Nathang two posts above and it all suddenly clicked. The lever was preloading the plunger too much and not allowing the relief port to get exposed. The difference was that cap. So instead of cutting the cap, I hand fit the levers 'nub' that makes contact with the plunger. Now, in the future, there is no chance of this happening again.

So thank you, Nathang, for that post. I was about to rebuild or replace the whole dang system.
 

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I hate necroposting for my first post...
"Necroposting" ! I love it, what a great new (to me) expression..
To your credit, most people who reply to a 12 year old post don't even notice it is long dead, and are frequently real animated about the topic.
It is really not a bad thing when an old post that might prevent a spontaneous crash at speed gets re-posted. It could have saved some people way back then, it probably could again now.
Welcome Swine Flew.
 
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