ABS System Testing and Maintenance

Attached find the procedure to test the ABS system using a jumper or switch at the ABS connector (see photo). Credit goes to "Professor Ionbeam", Alan has contributed much with his knowledge of all things electrical and more. I installed a mating connector in my ABS connector and have a...

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Thanks, I will try the test procedure.

 

So I did both tests and.. yep. Something's definitely wrong. ABS motor buzzes, so that's good, but the pulsing on the lever is very faint, almost not detectable. As "offspring" is only 3 years old and not qualified for the job, I assigned "wife" for rear wheel rotation duty, and wheel wouldn't move upon the second pulse, not even a tiny bit. So the wheel is not unlocked by ABS, which is consistent with faint response on the levers.

I'm starting to think that there might be air in there. I recently took the bike to a local shop, and among others, the brakes and clutch were bled. I've checked after I got the bike back: the fluids were indeed replaced and brakes were firm so I assumed they did everything they were supposed to. But just now, when I did the test the first time, the front brake lever collapsed in till halfway point on the first pulse. This only happened the first time - I've repeated both tests 5 times and it didn't happen on subsequent tests and there was no improvement on pulse intensity.

Is there a special way to properly bleed the air out of the ABS unit which I can try before taking the motorsickle to a $80/hr shop to investigate this further?

 

If the rear pedal and front levers are firm, there may be no air.... after your tests, I would just bleed again.
When bleeding rear, start with the right front caliper lower, then the rear. Give firm fast pushes on the pedal to move any air along. See if you get improvement. Repeating the ABS test is not a bad thing... if there was any dried fluid in the ABS circuits in the ABS pump, it should be moved along and fresh fluid behind it. A new bleed should purge it provided there is no blockage, fluid should flow freely. Tie the rear pedal down overnight to consolidate any air that may be in there, give a quick bleed after that.
After all that, for totally stubborn air, if you think you have some, you can loosen the banjo fittings at the ABS pump and push some fluid through..... can get a little messy, have isopropanol to rinse things down.
You can do this without paying $80/hr. and chances are do a better job..... once done, very important to flush/bleed these pre-'08 systems annually and run the ABS test.

 

Randomdude,

Speedbleeders.com can help. They will know what you need. Get their fluid-catch bag, also.

 

Another vote for speedbleeders - and their little plastic bag.

 

Did you notice there are two different methods to the test? I use method #2. A lot less sweat, can be repeated indefinitely and no helper needed.

 

Bled the whole system again. I pushed out (and put back, of course) about .2 litres of fluid altogether. There were some miniscule amount of air at the front, but absolutely no change whatsoever. Lever and pedal still feels the same (firm), and ABS still doesn't work**. I did the bleeding all by myself, you can reach all bleeding nipples while holding the lever/pedal so I don't see the benefit of that speedbleeder thing.

But I was thinking, the 12.8V that the FSM keep referring to, is that with or without ignition on? Checked my battery, 12.85 with igntion off, 12.5 with igntion on. Well, even if maybe this tampers with the ABS tests, still doesn't explain why the ABS doesn't work while the bike is moving as the voltage is already 13.3V even at idle.

What I did notice this time is that during tests, the ABS light was flashing slowly and constantly (like 1/sec), as opposed to last time when it was flashing rapidly (like 3/sec) and in bursts. Also, last time, I got the ABS error codes after the first test, this time I did both tests several times, and no error codes, which seems pretty weird.

I'm reluctant to undo the banjo fittings because a. as you said, it would make a huge mess, b. as I understand it, there is no pressure inside and air will seep in once the fluid drains out of the fitting.

** When I say "ABS doesn't work" I mean the pulse action during static tests are very weak. There is some pulsing force generated by the motor, but it's not nearly strong enough to overcome the force on the pedal/lever and unlock the wheel. I had an 08, the ABS on that literally kicked the lever out of my hand, so I know exactly what it SHOULD do.

I've ran out of ideas, but apparently this is a very common thing and a lot of gen1 and gen2 FJR's have non-functioning ABS's.

 

Myself, I would use the alligator clip method shown in Russ’s procedures above and excercise The pump some and bleed the system, I think that it may be “sludged” up a bit , lack of maintenance will do that. I do not believe it’s air in the system, so if excercise & bleeding doesn’t improve it then I believe it’s just bad and needs to be replaced. They do fail, It does happen

By the way, on an ABS system once it activates you just hold it solidly, don’t pump the system ! It empties their small sumps which then causes the lever/pedal To go to their full stop with a no brake condition, not good !

 

It sounds like you have no air.... if your brake lever and pedals are firm, we'll assume so.
Yamaha says battery voltage must be 12.8 to run the test, which means, fully charged battery... so 12.5 with ignition on seems reasonable.
Weak pulses - perhaps subjective, but should be quite noticeable. If both front and rear pulses are similar, that's the main thing...... and the fact you have them. I haven't heard of ABS issues on the front, the vast majority if not all were on the rear due to clogging of the ABS portion of the fluid circuit within the pump (between points 5 and 7 in diagram). In any event, consider activation of the ABS test say once a month for the rest of this year and see if anything improves (stronger pulses).
The big test (and consider the risks) is if you can skid the front or the rear wheel, to verify ABS is actually working. Testing the front is easier than the rear, I was never successful testing the rear as I didn't have the right conditions. The ABS doesn't work below a certain speed (~20 mph, don't quote me) be aware... know your risks....

 

Since then, I've bled the brakes again - still no air. I've clocked up ~1200km last weekend, half of it through twisty mountain roads at peg scraping pace with hard braking before every corner. Many many occasions of wheel slippage when ABS should have intervened, but didn't so I guess it has been excercised enough. Still no change, if I stomp the brakes it will skid, both front and rear.

FWIW, I perfected my threshold braking technique so who needs ABS anyway
j/k, ABS is very useful, especially in the wet/cold.

P.S. these Michelin Road 5 GT's are fire! They grip like crazy from stone cold and give maximum confidence in corner and during braking, too. I was reluctant to buy them because I've had bad experience with so called "sports touring" tyres in the past (lack of grip, vague handling), but this is just perfect for the street and beats (or is on par with) all other "sports" tyre I've used in the past.