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Discussion Starter · #1 ·
I've been riding my bike for 5 months on new tires...front a Dunlop Sportmax and the rear Michelin Pilot. The Pilot is fine and the tread deep. The Sportmax is worn nearly bald on the front. Ordered the Pilot for the front and will get it put on Saturday. I'm not really complaining, just noting how free (which the front tire was) isn't always best...but it did get me 5 months of riding. :)

Now my next task...figure out what has gone sour with the rear ABS braking. Draining and bleeding the lines have no effect, which leads me to think the problem is in the ABS hydraulic system. Front brake fine...so I ride. ;)
 

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what is this rear brake thing used for? The only time I've ever touched it is during msf classes because they demand some rear application.
 

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I'm not really complaining, just noting how free (which the front tire was) isn't always best...but it did get me 5 months of riding. :)
I got six months out of the stock front tire...from 2004. Bought the bike with 4k in January, now it has 11k. Not exactly the safest thing to do, but it works.

A new Q2 should arrive tomorrow. Definitely looking forward to being able to trust the tires again, haha.

The stock front wore pretty well on the highway, which is most of what I ride, but I wore the corners off it pretty quick once I got the hang of riding on the street.
 

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Discussion Starter · #5 ·
What is the rear abs doing that makes you think there is something wrong?
The rear brake isn't engaging at all. Pressure to the lever results in a whisper noise. Caliper redone, hoses drained and bled, all leveled up....nothing. Only other thing I can think of is the ABS hydraulic system is messed up. The brake lever went rock solid when I was down shifting while applying both brakes thanks to a pickup truck stopping dead in front of me on a blind curve.

As long as I don't lose the front...alls good to keep riding.
 

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Discussion Starter · #6 ·
what is this rear brake thing used for? The only time I've ever touched it is during msf classes because they demand some rear application.
Lately it's just been a foot rest. :lol:

I've only had to use it a couple times for a couple quick stops...other than that, my toe sits under it. I guess I get a bit of comfort knowing if my front fails, I have a backup. No backup now....will have to resort to a Barney Rebble stop if the front decides to act up. ;)
 

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The rear brake isn't engaging at all. Pressure to the lever results in a whisper noise. Caliper redone, hoses drained and bled, all leveled up....nothing. Only other thing I can think of is the ABS hydraulic system is messed up. The brake lever went rock solid when I was down shifting while applying both brakes thanks to a pickup truck stopping dead in front of me on a blind curve.

As long as I don't lose the front...alls good to keep riding.
Bleeding ABS is more involved than bleeding regular brakes. Please get a manual and do it right, or take it to a pro to have it done. This is a serious safety issue and should not be neglected.
 

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The rear brake isn't engaging at all. Pressure to the lever results in a whisper noise. Caliper redone, hoses drained and bled, all leveled up....nothing. Only other thing I can think of is the ABS hydraulic system is messed up. The brake lever went rock solid when I was down shifting while applying both brakes thanks to a pickup truck stopping dead in front of me on a blind curve.

As long as I don't lose the front...alls good to keep riding.
I don't have the service manual for the SV ABS system, but ABS systems are typically designed for failsafe operation. I would be amazed if the SV system was not. Failure should result in normal, non-ABS brake operation. That is, your brakes should still function, just without the antilock feature. With the key in the off position, put the bike on a rear stand, spin the wheel by hand and press the pedal to see if the rear brake works. If you don't have a rear stand, have someone push you or try duck-walking the bike with the key in the off position and press the rear brake pedal to see if you have rear brake. The key has to be on for the ABS to activate, and typically ABS will not activate unless the bike is moving at about 10 mph or more. If the rear brake works normally with the key off but does not work with the key on it might conceivably have something bizarre to do with the rear brake ABS activating spurriously, but it is highly unlikely.

What do you mean by "the brake lever went rock solid" and was it front or back? Let's refer to the rear as a pedal and the front as a lever to avoid confusion.

It is more likely that something is screwed up in the non-ABS part of the rear brake system (caliper/pistons/pads, master cylinder, etc.) than a problem with the ABS hydraulics or electronics.
 

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Discussion Starter · #9 ·
I do have my mechanic looking into it...I know I'm outta my league with this one.

To clarify, the pedal went rock solid...wouldn't move down or up...acted like it was welded in place.

We have done the key off roll and brake and the brake didn't engage. No movement at all.

Also, when I describe a whisper...I guess it's like a shoosh sound...like the sound coming out of an empty turkey baister. No pinhole in a line, no air in the lines, no weak clamps.

Looking forward to the new tire on saturday though! I have a day of riding planned that's going to take me all over central Florida.....all ending at Oldtown to enjoy some classics! :)
 

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I do have my mechanic looking into it...I know I'm outta my league with this one.

To clarify, the pedal went rock solid...wouldn't move down or up...acted like it was welded in place.

We have done the key off roll and brake and the brake didn't engage. No movement at all.

Also, when I describe a whisper...I guess it's like a shoosh sound...like the sound coming out of an empty turkey baister. No pinhole in a line, no air in the lines, no weak clamps.

Looking forward to the new tire on saturday though! I have a day of riding planned that's going to take me all over central Florida.....all ending at Oldtown to enjoy some classics! :)
Good luck. Let us know what the problem was when it is resolved.
 

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Does the ABS light come on when you initially start the bike? Does it then go off after you speed up?

Could also have pulled the ABS fuse to see if things return to normal.

Guess it's a bit late for things now... What's odd is that the front brake is functioning normally. (correct?) Usually a hard pedal on an ABS system that uses a pump means either the pump or accumulator has failed. If the front brake is still fine, then perhaps there's an issue with the valve body?

A new ABS unit is hilariously expensive, unfortunately.
 

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Discussion Starter · #13 ·
Does the ABS light come on when you initially start the bike? Does it then go off after you speed up?

Could also have pulled the ABS fuse to see if things return to normal.

Guess it's a bit late for things now... What's odd is that the front brake is functioning normally. (correct?) Usually a hard pedal on an ABS system that uses a pump means either the pump or accumulator has failed. If the front brake is still fine, then perhaps there's an issue with the valve body?

A new ABS unit is hilariously expensive, unfortunately.
ABS light on with turn key and off at acceleration. And yes, front working fine.

This one has me puzzled and I'm new to ABS. I just keep learning as I go....;)
 

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ABS light on with turn key and off at acceleration. And yes, front working fine.

This one has me puzzled and I'm new to ABS. I just keep learning as I go....;)
I'm not very knowledgeable on ABS, so I'd like to know what the issue was. Perhaps the SV's ABS unit has a separate accumulator for the front and rear brake? Maybe air got trapped in the valve body or accumulator somehow? Who knows.
Unfortunately I've never really had the chance to take an ABS module apart and tinker with it. The designs are also quite varied amongst manufacturers...
 

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...Could also have pulled the ABS fuse to see if things return to normal.
Problem occurs with key off, no need to pull fuse. Only ABS failure mode I can reasonably think of would just render ABS inoperative, not lock up brake pedal and prevent caliper operation.

Let them sort out the bugs first before I buy a bike with ABS.
What bugs are you talking about? Wanna bet this has nothing to do with ABS?
 

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I have an 08 ABS model as well. Are you using a vacuum pump when bleeding or just pedal/lever pressure? With the MCs, the hardlines that go to the pump and the lines that finally make their way to the three calipers, there is quite a bit space for trapped air bubbles. I usually pull about 3-5 reservoirs full of DOT4 through the rear system before I feel comfortable with a bleed job. even more for the front system.

David is correct that our ABS function is failsafe. It defaults back to normal braking function when there is an error or when innoperative. I disable mine for track use because the SV's system is quite conservative and pretty choppy when it activates.
 

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Discussion Starter · #19 ·
I could try a vacuum bleed again with a longer pull on fluids.

How do I bypass or inactivate the ABS? Not thinking of it as a solution to this problem, but have wanted to do it since I bought the bike.

Thanks everyone for the input so far. I will post what is found out. I'll ask my mechanic to do the vacuum bleed when he changes out my tire on Saturday...maybe I can post a success :lol:
 

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A few options on deactivation.

1. Disconnect the wiring plugs going into the ABS pump/valve body which hangs right behind the rear shock.

2. Pull the ABS fuses which are underneith your front seat, next to the starter solenoid.

3. Do a 2-3 second wheelie that will give a BIG wheel speed differential reading at the ECU which in turn will trip the ABS cut off. :evil6: :vroom:

4. For complete bypass, purchase a set of non-ABS model brake lines and bypass the system alltogether. Plug the ports at the end of the hard lines with 10mmx1mm flare caps.

Option 2 is obviously the easiest. 4 is the most complete and should only be used as a last resort. 1 leaves the plugs open to corrosion and 3, well...........I'VE never done it.....I just heard about it.......:hiding:
 
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