How do you know ABS is working on an '07?

[ELP_JC]

Hi gang. Few facts first: Bike has 1,632 as of this moment, is 16 months old, and already did a full brake bleed once. ABS light flashed once during my last trip with a semi-aggressive stop (for a break on a desolated highway, at about 65ºF). Never happened again, and all lights turn on with ignition, and off when motor starts, supposedly indicating all systems are okay. Oh, and I was told by a member ABS light flashes when ABS is engaged (need more info on this).

The above 'flashing' incident prompted me to test my ABS this afternoon. I locked my brakes three times, from about 30 mph, and ABS light didn't turn on at all. Maybe it was too quick to start flashing, who knows. But more disturbing, I felt the horrible chatter that results from locking the front wheel (twice), for those who know how it feels (thanks to Superbike School). The third time I tried to lock the rear, and don't know if it happened or not, but didn't feel anything on the pedal. I thought I heard it skid, but could be wrong. Didn't feel any instability on the bike either, but it was straight. I personally doubt a heavy bike like the FJR can lock the rear wheel on dry pavement with only 1 piston (and diverting pressure to 2 front pistons), but could be wrong too. Comments welcome.

- I'd like to know how ABS engagement feels on your '07, and hopefully with front and rear brakes independently applied.

- I'd also like to know if there's an alternative way to test the system (especially the motors), as locking wheels is pretty abusive for both tires and suspension. Not to mention dangerous if ABS is not working properly.

Bike idling on centerstand only checks sensors, right? I thought about a gravel road, but it'd have to be at speed, so prefer to find out in a different way. There's a complicated procedure that techs can perform; I can look it up on my service manual, but tank and inner front panels need to come off and short some wires. Wish it was possible to fire them up with the diagnostics, but am almost sure we can't. Once motors are known to work, the centerstand method could confirm sensors are working, rounding out the test, no? That's why I liked about my BMW servo brakes: the servos powered both the brakes and ABS, so if you had brakes (and no lights), you had ABS. The fact you never hear the motors 'whirr' has me doubting the ignition 'self-check' really works. And the front wheel never chattered on my BMW like on this bike. Maybe that's why Yamaha changed the system in '08? Maybe it reacts quicker? Again, my goal is just to make sure ABS is working properly. Thanks in advance for your valuable help.

JC

 

[200cs]

i check mine often by taking it out to a semi deserted area and hammering the throttle in first and then use the reae brake only to stop the bike as hard as you can. You can feel it want to slide then you should hear some clunking letting you know the abs is working. Good luck trying it with the front brakes, they are just too good.

 

[mcatrophy]

QUOTE (ELP_JC @ Sep 21 2008, 10:04 PM) ...

- I'd like to know how ABS engagement feels on your '07, and hopefully with front and rear brakes independently applied.

- I'd also like to know if there's an alternative way to test the system (especially the motors), as locking wheels is pretty abusive for both tires and suspension. Not to mention dangerous if ABS is not working properly.

...

JC

On my '06 (which I believe is the same as the '07, there may have been a change for the '08/09?), when the rear is applied hard on a dry, good grip road, it leads to relatively mild rapid pulsating. The front feels more positive in its pulsating, but doesn't cause any violent shakes (as some systems do). In both cases the decelaration is very impressive (as you might expect).

I've also tried on wet, moderately slippery roads. If you weren't looking for it, you might think the bike had gone over corregations in the road. Again, no drama, just quite surprising retardation.

FWIW my tyres are Bridgestone BT021s. Don't care what anyone says, they suit my type of riding on my type of road, except perhaps this sort:

[EDIT] I take back that line about BT021s. The front is a POS after about half worn. BT023s are fine.

(click on image for larger view)

A flashing ABS light usually means a problem, I had it happen when my rear brake lever was sticking on (see here).

As for testing, remember that if the ABS is working, the tyres aren't wearing as much as a bike without ABS, so an occasional test doesn't add much to tyre wear. Just choose your moment (going straight, no-one on your 6), progressivly squeeze one or the other (or both) until you feel it happen. Any road surface, dry, wet, ironwork, lines, gravel, don't care. Learn what it will do, you'll be happier to use full braking when you really need to

.

Oh, yes, the rear brake is definately strong enough to lock the rear wheel on a good surface if there was no ABS.

 

[ELP_JC]

Thank you for those great replies; greatly appreciated.

My brakes are probably working okay, ABS just seems to react slowly before engaging. And yes, '06 and '07s are the same; system changed in '08. I'll have to test my brakes where I can lock them a little longer to feel the system engage (hopefully) for sure.

What doesn't inspire confidence is the 'self check' feature, if any. The BMW activates the motors, then the ABS flashes until you roll the bike enough for the ABS computer to check both sensors are working properly, then it goes away; THAT'S a check I could trust. I don't know what the heck the FJR checks; probably nothing, but will try to find some reading about it on the service manual. That's why I want to make sure they work, although I know for sure they are not as quick as they should ('08 bikes probably are)... but better than no ABS B) . And as you guys said, it's always a good idea to be familiar with maximum braking anyway. And it's good to know you can lock up the rear tire alone, and that the ABS light doesn't flash while engaged; thanks. Have a great day gang.

JC

 

[Duff]

The ABS on my 05 was pretty fast and saved my arse a couple times. My 08 seems to work the same, although I know it has one more "mode" that my 05 did not have.

I "check" my ABS when the conditions present themselves. Wet weather and a clear road gives me a chance to "feel" the motors working and remember what it is like in case I need them in a panic.

It does seem strange that there is no feedback, other than lights on and back off, for the system, but it might be a little strange if it worked like some cars. My Honda has a "bump" just after I start driving it that is related to the ABS operational check. Might be a little unnerving to have the FJR give me a "bump" as I start to ride it after a startup. :blink:

Regardless, the system works unless the light comes on and says it doesn't. Give it a try...

 

[mcatrophy]

Thank you for those great replies; greatly appreciated. My brakes are probably working okay, ABS just seems to react slowly before engaging. And yes, '06 and '07s are the same; system changed in '08. I'll have to test my brakes where I can lock them a little longer to feel the system engage (hopefully) for sure.

What doesn't inspire confidence is the 'self check' feature, if any. The BMW activates the motors, then the ABS flashes until you roll the bike enough for the ABS computer to check both sensors are working properly, then it goes away; THAT'S a check I could trust. I don't know what the heck the FJR checks; probably nothing, but will try to find some reading about it on the service manual. That's why I want to make sure they work, although I know for sure they are not as quick as they should ('08 bikes probably are)... but better than no ABS B) . And as you guys said, it's always a good idea to be familiar with maximum braking anyway. And it's good to know you can lock up the rear tire alone, and that the ABS light doesn't flash while engaged; thanks. Have a great day gang.

JC

If you expect the wheels to "lock", they won't. The ABS prevents this, so if that's what's worrying you, don't!

Just try testing them, just squeeze/press as hard as you can (while in a straight line). You will simply slow pretty rapidly. And, that's the best check you can give.

 

[Mike101]

They work on mine. I found that when I stopped quick in the garage. The front brake pulsated and did not lock until I was stopped. Was not going that fast either. The floor is slippery.

M

 

[ELP_JC]

If you expect the wheels to "lock", they won't.

Actually they do... momentarily; that's when the ABS computer gets the signal. Think about it, and it only makes sense. Once a wheel locks, ABS is supposed to kick in immediately afterwards.

Anyway, what I meant was to go fast enough that wheels can lock (or not) enough to feel ABS working before stopping. I'm an aggressive rider, and am pretty comfortable with hard braking. Since this bike is new to me, I'm doing the testing now. As I said, I have no doubt I locked the front wheel twice (I tried it many times at Superbike School, so know how it feels -under controlled conditions there-, and when you start losing the front), but was stopped a moment later. Need a bit longer to give ABS a chance to engage, as it probably takes longer than the fraction of a second it took from the tire to lock and the bike to stop. I also want to feel how quickly it reacts to lock-up. I know it's slower than my BMW for sure, but that bike was a lot more expensive, so it's understandable. Proof of that is the number of 'teeth' inside the ABS sensor; the BMW 'ring' had probably 3 times as many (much larger than the tiny diameter of the FJR). I'd also like to find out what exactly was changed on the ABS of '08 bikes. And I have my doubts the whole system is checked, hence this thread. Thank you too for your great help.

JC

 

[Malve]

My abs kicks in every so often on my '06 and it is plenty noticeable. If you can't get them to activate, you MAY not be breaking hard enough. In a safe, controlled environment try a little more aggressively.

 

[madmike2]

If you expect the wheels to "lock", they won't. The ABS prevents this, so if that's what's worrying you, don't!
Just try testing them, just squeeze/press as hard as you can (while in a straight line). You will simply slow pretty rapidly. And, that's the best check you can give.

One might assume. by the tenor of the conversation, that he meant to find an empty parking lot or deserted road and accelerate, then brake to the threshold at which the ABS activates. At least that's what I interpreted him to say. I know I can get mine to activate from 20-25 mph by rolling off the throttle while squeezing to maximum braking.

Er...uhm...you all DO practice this regularly, don't you? Rears, then fronts, then both? I mean...just so you'll be prepared in case an emergency situation occurs during which you might need to know exactly how your bike will react to your braking and steering inputs? I'm just sayin'..... :blink: Of course, I'm no professional nor am I an MSF instructor or connected with any safety organization. I'm just a regular citizen motorcycle rider who tries. :huh:

 

[mike25]

Find an open road, accelerate to 100mph, grab a handful of front

brake, and mash the rear. You'll feel the ABS activating, and come

to a controlled stop.

Repeat as above. Only this time after you feel the ABS kick in, back

off , and try to stop as quickly as you can without the ABS.

I felt a very noticeable increase in stopping power without the ABS

bring activated. (internal 'G' meter only, no actual measurements).

That being said, ABS is a great feature to have on a motorcycle.

My last crash was because of a front brake lock-up. Some bimbet in

a SUV chopped my *** bad on my ZRX (yes I panicked, and know better).

 

[mcatrophy]

QUOTE (ELP_JC @ Sep 23 2008, 12:03 AM) <{POST_SNAPBACK}>

QUOTE (mcatrophy @ Sep 22 2008, 02:04 PM) <{POST_SNAPBACK}>

If you expect the wheels to "lock", they won't.

Actually they do... momentarily; that's when the ABS computer gets the signal. Think about it, and it only makes sense. Once a wheel locks, ABS is supposed to kick in immediately afterwards.

JC

Without wanting a "they do

they don't" argument, they don't lock! The ABS sensor detects one wheel slowing more than the other and backs off the braking effort to that wheel to prevent it locking.

One of those non-intuitive factoids is that the maximum grip of a tyre occurs with slight slipping, if memory serves (and it often doesn't at my age), something like a 10% slip on a dry road gives the maximum, whether accelerating, braking or cornering (I'm not saying ABS holds it there, it doesn't).

For what I think is an excellent real-world test of ABS on motorcycles, read this. Although done some years ago, it's still very relevant.

 

[ELP_JC]

Without wanting a "they do :argue: they don't" argument, they don't lock!

And how do you know? Just look at the FACTS. Don't have my BMW with me anymore, but all of them have a ring just below the rotor (I'm sure you're familiar with them), that I'm guessing has at least 100 holes, or an accuracy of 3.6º (100/360). The FJR seems to have 20 at the most, or an accuracy of 18º. Leaving the computer's brain power alone, they can't react any quicker than the input from the sensors. If you see '08 bikes, they have much better 'accuracy' with their new (now exposed) 'ring', so your argument might hold a candle on '08s, but not '07s. Not all ABS systems are created equal, just like you can't expect to have the same accuracy with the same rifle from 200 yards with and without a scope. The scope is like the difference of # of signals the BMW and '07 FJR sensor detects per revolution, but it's not obvious to most owners. There's a 'Mercedes' and 'Geo' of EVERYTHING (you name it: leather, refrigerated A/C systems, guns, bicycles, etc), but many times we're not familiar with the product to know any better.

Now, I know for a fact my ABS DOES NOT activate before lockup, and the heavy scars on my front wheel from those 2 tries are proof of it. I certainly don't appreciate the expressed or implied 'you don't know how to brake' crap, but guess it's expected. Don't see this thread going anywhere, and certainly never intended to turn into a pissing contest, so will sign myself off. You guys can continue it if you want.

Will probably end up activating the motors thru the procedure outlined in the service manual during the winter, and do a 2nd full TB synch (did the first at only 600 miles) now that the tank will be up. Once I know the motors are working for sure, will do a high-speed test, just like I said (and Mike25 suggested... but not from 100 :blink: ), and feel how quickly (or slowly :huh: ) the system reacts. And no, I don't rely on ABS for panic braking, but it's nice to know it's there. And it's certainly VERY important to be familiar how it feels and works before you need it. Later.

JC

 

[mcatrophy]

QUOTE (ELP_JC @ Sep 23 2008, 07:34 PM) <{POST_SNAPBACK}>

QUOTE (mcatrophy @ Sep 23 2008, 01:27 AM) <{POST_SNAPBACK}>

Without wanting a "they do

they don't" argument, they don't lock!

And how do you know? Just look at the FACTS. ...

JC

Two comments:

1. Please read this link, you might actually learn something (it's on the Internet BMW Riders web site). One quote from it:

QUOTE

Instead of waiting for a wheel to slide before taking action, modern ABS systems can actually predict wheel lock-up before it happens and begin to ease off the brakes.

And this was 1991/2.

2. If you are getting flat spots on your tyres, your ABS is not working properly. I've tested mine many times and never flat spotted a tyre.

Only trying to help.

You'll be pleased to know I can't post for a week, off to Scotland

. 'Bye for now.

 

[just roy]

not to be a spoil sport but if you grab a hand full of front brake really fast you can get a chirp from the front wheel. I can do it on my 08 and could do it on my BMW. but under normal braking with a firm squeeze you should never lock up a wheel until the speed is almost zero and the sensor wheel is going very slow giving poor resolution. if you don't feel your brakes are working properly i would think a sane person would have them looked at by a professional instead of playing around and asking advice on the internet. you repeatedly spout about the superiority of your BMW so why aren't you still riding it. your comments can only draw negative feedback on this site and make you look like a troll. if this bike is such an inferior POS you should get rid of it because you will never have any confidence in it.