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Discussion Starter · #1 ·
I need some help.
Sorry about the long story, but I think it may help.

I had my local shop install my new Cobra Tri-pro exhaust. (Awesome by the way). But after they got done and test drove it, the rear brake caliper hung up while he was test driving it. He got back to the shop checked the free play on the lever, adjusted it and rode it again, said it did fine. The service manager even rode the bike after him and said it did fine. I watched the install on the pipes and he didn't do anything to the brakes other than move the right side foot peg and brake lever. So I was I okay with that, figured it was a fluke and it was resolved. Got my bike, headed down the road, made it about 5 miles and guess what? yup. Bike starts boggin down pull over into a parking lot and when I clutch it, stops on a dime. Rotor is hot as snot. Jump on the phone, they send a truck with trailer to pick me up. By the time he gets there brake releases. Get it back to the shop, they inspect the fluid, cloudy and old, brownish. They flush thoroughly, check all the adjustments and everything seems great. They think that maybe with the fluid condition something may be clogging the return port in master cylinder. Everyone rides it again, everything seems good. I get the bike back, even take the long way home. Everything seems great. Ride several short rides and everythings good. Yesterday, put decent ride on her, and at the end of the day, in slow moving traffic, guess what. Yup, shoulder of the road. Took my foot and tapped the brake lever and it released. Stopped and got something to eat. Rode it the rest of the way home, did good.

I'm concerned because I'm planning on leaving for a 600 solo trip up the Outer Banks on Thursday and right now I don't trust my bike. Any suggestions?
 

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Lubrication

This could be something as simple as lubrication of the pivot in the brake lever.

There is a pretty long bushing for the R brake and it should be lubed from time to time with some oil. If it hangs even slightly (the spring is unable to return it to the fully retraced position) the fluid will be held in the caliper.

Also make sure that nothing is preventing full retraction of the lever. Including your foot. I know, I know, you know it's not your foot. Just had to bring it up as the position of the R brake lever from the factory is horrible. I had to bend it out of the way so I had a place to put my foot.

Tracy
 

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check the rear brake fluid reservoir, you might have a too much fluid in there.
 

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Discussion Starter · #4 ·
I checked the brake lines and cant find any damage to the hard lines and the rubber lines don't look swollen. The pedal moves freely, didn't feel any binding. The previous owner had already done the mod where you slight bend the part that your foot comes into contact with the pedal(which is good, as I have big feet.
 

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Here is something you can try. Go for a ride, take a wrench w/ you that fits the bleeder. When the condition occurs, pull off and loosen the bleeder. If it frees up, you have something keeping pressure in the line. If it doesn't, you have a sticking caliper.

When the condition occurs, does the brake pedal return to the resting position or does it hang up? As Paladin already stated, I would def be looking in that area since it wasn't an issue before.
 

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Discussion Starter · #6 ·
Here is something you can try. Go for a ride, take a wrench w/ you that fits the bleeder. When the condition occurs, pull off and loosen the bleeder. If it frees up, you have something keeping pressure in the line. If it doesn't, you have a sticking caliper.

When the condition occurs, does the brake pedal return to the resting position or does it hang up? As Paladin already stated, I would def be looking in that area since it wasn't an issue before.
I did notice something, where the push rod goes into the master cylinder, it looks like it's going in at an angle not straight. I don't see any adjustments or shims that would change the position of the lever on the end of the rod or the angle of the master cylinder. I checked the foot peg bracket, doesn't look bent. Is that normal, has anyone ever looked at their's from underneath?
 

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MC cap vent

Make sure that the vent in the MC cap is clear. It is usually a small hole in the corner that terminates above the bellows. If it gets loaded with dried brake fluid it will prevent the bellows from moving. As the fluid warms and expands it needs somewhere to go. If the vent hole is plugged it will put pressure on the caliper.

I would also look at the linkage adjustment near the MC. If the return stop isn't adjusted properly it will prevent the piston from returning completely blocking the port.

Tracy
 

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Heat?

I might be your new exhaust heating up the fluid in the brake line and the resulting expansion is what is applying the brake!
 

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Welcom to my summer.

I fought with this exact issue for three months.

I have had the rear brake system torn down and built back up so many times I can now do it in my sleep.

My issue was that my one piston had gotten off line slightly and scratched the inside of the caliper. A hone took care of it and all is well now.

Good luck.
 

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Discussion Starter · #10 ·
I might be your new exhaust heating up the fluid in the brake line and the resulting expansion is what is applying the brake!
I thought about that too. That new exhaust doesn't seem to be any closer to the brake lines than the stock. Matter of fact, without the cat, I would think it is now further away. Even back at the swing arm it looks further away(I think).
 

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Discussion Starter · #11 ·
Welcom to my summer.

I fought with this exact issue for three months.

I have had the rear brake system torn down and built back up so many times I can now do it in my sleep.

My issue was that my one piston had gotten off line slightly and scratched the inside of the caliper. A hone took care of it and all is well now.

Good luck.
That's the part that I don't understand, here at the coast we have some seriously hot days. Haven't had the first problem with the brakes until the exhaust was put on.
 

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That's the part that I don't understand, here at the coast we have some seriously hot days. Haven't had the first problem with the brakes until the exhaust was put on.
I hear you, but it apparently does not take much external force to set the piston up off-line.

For mine, the heat was an issues in that the piston and caliper expand at different rates, so the hotter the systyem got, the more it stuck.

I warped a rotor, burned through 2 sets of pads, flushed and changed the fluid 5 times.

Once I finally broke down an tore the caliper apart, you could see scratches in the piston and inside the caliper.

If I were closer, I would check it for you, but I can walk you through it if needed.

I am just not sure anything else explains why you are seeing my exact set of issues.
 

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I did notice something, where the push rod goes into the master cylinder, it looks like it's going in at an angle not straight. I don't see any adjustments or shims that would change the position of the lever on the end of the rod or the angle of the master cylinder. I checked the foot peg bracket, doesn't look bent. Is that normal, has anyone ever looked at their's from underneath?
I just looked at mine, the rod doesn't go in at an angle. While looking at the master I did notice the adjustment rod, has nuts on either side of it. Do you know if they took that apart.
If they did, that could be the problem if it's adjusted incorrectly. That's why I told you to try the test I posted above. If it's adjusted to tight, once the fluid gets hot and expands, if there is too little travel in the adjustment, it will cause the brakes to drag cause there's not enough room for expansion.
 

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I'll offer this tidbit, compliments of when I installed the Tri-Pro on mine.

Yes, you have to remove the whole foot brake lever assembly to install the pipes. When I did so, there is a spring on the assembly that pulls the lever back to the rested postion. This spring somehow came off and was just dangling off the brake lever. Took some doing with some needle-nosed vise grips, but I got it back on again.

Check this. That lever is quite large and heavy, and the spring is quite strong. Mayhap the spring on yours is off as well, and not fully returning the lever to its rested position.

Cheers.
 

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Discussion Starter · #15 ·
I just looked at mine, the rod doesn't go in at an angle. While looking at the master I did notice the adjustment rod, has nuts on either side of it. Do you know if they took that apart.
If they did, that could be the problem if it's adjusted incorrectly. That's why I told you to try the test I posted above. If it's adjusted to tight, once the fluid gets hot and expands, if there is too little travel in the adjustment, it will cause the brakes to drag cause there's not enough room for expansion.
I'm going out for a ride this afternoon, I'm gonna try what you suggested. It's just weird, cause yesterday when it was hanging up, I thumped the lever with my hand and I could feel it release. I did take the shield off and the bolts that hold the master cylinder, and checked the travel of the push rod. It's coming all the way back to the rested position. I also checked the return spring it is intact. But it still doesn't go straight. Looks like it's at an angle and there is no way that I can see to get it straight. I'm taking it back to them on Tuesday.
 

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This is what it looks like.
It's friggin bent,,,,,,,,,,Looks like the exhaust didn't fit and they had to bend that to fit? I hope that isn't the case, That would be some chit work man,,,,,,,,,,,,something isn't aligned true, Maybe the cylinder wasn't put back on right or they had to bend the bracket it mounts on,,,,,,,,,
 

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It's friggin bent,,,,,,,,,,Looks like the exhaust didn't fit and they had to bend that to fit? I hope that isn't the case, That would be some chit work man,,,,,,,,,,,,something isn't aligned true, Maybe the cylinder wasn't put back on right or they had to bend the bracket it mounts on,,,,,,,,,
I never had to mess with the master cylinder at all when I installed the Tri-Pro. All you are supposed to do is remove the bracket with the pedal. It all comes off as one piece, two bolts. Never had to bend anything to get it to fit properly. If they did that, they did something wrong.

Definitely take it back to them. Boneheads.
 

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Discussion Starter · #19 ·
I never had to mess with the master cylinder at all when I installed the Tri-Pro. All you are supposed to do is remove the bracket with the pedal. It all comes off as one piece, two bolts. Never had to bend anything to get it to fit properly. If they did that, they did something wrong.

Definitely take it back to them. Boneheads.
I watched him. All he did was move the pedal/foot peg assembly. There is only two bolts that hold it to the frame. There aren't any signs of impact or stress to the frame or the foot rest bracket. I've had the bike for a year and it's never been down. I dunno. There isn't any adjustment or shims.
 

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Wrong!

Something is not assembled correctly. It's hard to tell what, but look at how close the inside lever is the this bolt in your photo.

The lever might be rubbing on it.
Your photo shows the plunger going in at quite an angle, it should be dead straight.
 
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