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Discussion Starter · #1 ·
The front brake lever on my (new-to-me) 1999 Speed Triple has *much* too much travel before it starts to gain pressure and bite. It's not spongy, it just travel a long way (half way back to the bars) before you get any resistance on the lever. A second 'pump' will improve things marginally, but after release, it's back to square one. Once you've got resistance to squeezing the lever, braking seems fine, althought the lever is dangerously close to the bars by then.

Braided hoses; fluid looks a bit yukky; I wondered about an internal leak in the master cylinder. Your thoughts? :confused:
 

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Try this: with bike on sidestand, turn bars full left, pull lever taught and lock it in that position with a zip tie or similar. Let it sit over night and the morning, remove tie and check lever firmness.

Fluid should be changed out yearly.
 

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Try this: with bike on sidestand, turn bars full left, pull lever taught and lock it in that position with a zip tie or similar. Let it sit over night and the morning, remove tie and check lever firmnes
IF that works, it means there is air in the system.
 

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Check to see if your pads are worn out. I put a new set of pads in the front of mine, and now have almost no lever travel. Bleeding is a good thing too...
 

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So here is how you can spend Sat morning...first, give a quick visual check of the pads, because no one puts new pads on a bike and then sells it, and all the hoses. Hopefully the hoses aren't mushy or bulging because that complicates things ( although it might simplify troubleshooting ). I'm gonna assume the pads are fairly worn ( see above ) and the fluid hasn't been changed in awhile ( because it hasn't ) and that you have some crud built up around the pistons ( because you do ). So, get thee to a bike shop...I don't know about the 99's, but the local dirt bike shop had pads in stock for my 06'...and get some fresh fluid, pads, brake lube/grease and either a real Mityvac or a cheap knockoff Mityvac from Harbor Hate.

Things you want to make sure of:
The area around and on the pistons is scrupulously clean, and the pistons extend and can be pushed back in with no drama or binding.
The pins that the pads slide on are clean and smooooooth...these get a little dab of brake lube, along with the pistons.
Use the Mityvac to bleed the brakes, swapping all the old fluid for fresh DOT 4 or DOT 5.1 ( NOT 5!)
Bam! Your brakes should work. And if they still don't, you have eliminated worn pads, sticky pistons, pads hanging on corroded pins, and bleeding/cruddy fluids as possible culprits.
Enjoy the ride, reward yourself with a frosty beverage after.
 

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The front brake lever on my (new-to-me) 1999 Speed Triple has *much* too much travel before it starts to gain pressure and bite. It's not spongy, it just travel a long way (half way back to the bars) before you get any resistance on the lever. A second 'pump' will improve things marginally, but after release, it's back to square one. Once you've got resistance to squeezing the lever, braking seems fine, althought the lever is dangerously close to the bars by then.

Braided hoses; fluid looks a bit yukky; I wondered about an internal leak in the master cylinder. Your thoughts? :confused:
Does your Speed Triple have the over-the-fender hose routing for the left caliper? If so, it is difficult to get the air out of the left hose because of the high spot in the middle. Best to get rid of that loop and to use two hoses from the master cylinder down. Bleed nipple banjo bolts also help.

The system should be flushed and bled every 2 years. By the time it looks "yukky" it's way too late, and it's likely that internal corrosion has already set in. If the seal grooves have corroded, at some point air will be drawn into the system every time the lever is released. If you keep getting groups of tiny bubbles during bleeding that never go away (in order to see them, use a flashlight under a clear bleed hose), this is likely what has happened.

Regards,

Derek
 

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Discussion Starter · #7 ·
Found the reason; what's the cure?

I've finally found the reason. With a caliper off the bike and a flat tyre lever in place as the 'disk', when I squeeze the lever hard, I can see the caliper body distort. Bascially, the two sides of the caliper are being forced apart. I roughly measured the deflection at perhaps 0.25mm. This was visible to the eye, which was why I measured... Both front calipers are doing it. No amount of bleeding is going to stop that!

What's going on? And what's the fix?
 

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I've finally found the reason. With a caliper off the bike and a flat tyre lever in place as the 'disk', when I squeeze the lever hard, I can see the caliper body distort. Bascially, the two sides of the caliper are being forced apart. I roughly measured the deflection at perhaps 0.25mm. This was visible to the eye, which was why I measured... Both front calipers are doing it. No amount of bleeding is going to stop that!

What's going on? And what's the fix?
I recently substantially improved the mushy brakes on two '99-'01 speed triples by installing T2020465 piston and seal kits. That may however not be enough to solve the problem to your liking. With the stock 14mm master cylinder, at 41.1:1, the master cylinder piston to caliper piston area ratio is not ideal (meaning that you have too much mechanical advantage). Installing a 5/8" master cylinder changes the ratio to a more appropriate 32.6:1. Considering the results from the change in pistons, I would try those first. I have found out that corrosion in the seal grooves is not likely to be an issue, as the insides of the calipers are anodized (not that common, Honda being the only other company I am aware of that does that). However dirt or other residues may be. Just be sure that you thoroughly clean the seal grooves before reassembling. S100 and a toothbrush, followed with a thorough rinsing with water and drying with compressed air work well.

Regards,

Derek
 

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I had similar problems on my '02 and trawled all the forum posts I could in the hope of finding an answer and getting my lever a little stiffer (watch it!) as I was used to on previous bikes.

Tried replacing the brake lines with twin race braided lines, changing the pads, "exercising" the pistons with a lever, switching the master cylinder, changing the bleed nipples...etc

Just about everything short of a hilltop sacrafice in the dead of night to the god of disc brakes.

While each thing I did helped a tiny bit - I wasn't happy with the lever travel until I pulled the calipers to pieces, cleaned them thoroughly, changed out the seals for fresh ones and covered my pistons in teflon grease.

Finally s**t hot brakes.
 

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Discussion Starter · #10 ·
While each thing I did helped a tiny bit - I wasn't happy with the lever travel until I pulled the calipers to pieces, cleaned them thoroughly, changed out the seals for fresh ones and covered my pistons in teflon grease.
I've got seals on order... here's hoping!
 
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