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Can I scrap HD's ABS system?

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Old 06-03-2009, 08:06 PM
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Default Can I scrap HD's ABS system?

I recently bought a 2005 FLHTP-I Police model. It has an anti-lock braking system, what I'm told was Harley's first attempt at ABS. The front left and rear rotors have a slotted disk riveted to them. (making it a $300+ rotor vs $130 for a regular rotor - the newer system lacks these slotted disks) The slots are read by an optical sensor to detect wheel lock-up. There is a pump or valve unit inboard of the right saddlebag. (using up half the saddlebag) The front brake line runs from the handlebar, into the fairing then along the bottom right frame tube back to this unit, then back forward along the frame to the front wheel. The back brake line goes into the unit also then to the back wheel. Needless to say I have brake lines running everywhere. There is an ABS light that comes on and blinks at start-up and goes off above 5 mph.

My question is, can I get rid of all this crap and just run regular, non-ABS lines? I think I can, as the manual says if the system ever fails, the brakes work as normal brakes. But am I going to be left with a contiuously flashing ABS light if I remove the system? Maybe I can remove the light? (inside the tach) Anybody with any Tech knowledge of Harley's ABS system, help me out.

Thanks...

Cage
 
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Old 06-04-2009, 08:06 PM
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Is there a fuse specific to the ABS system you can pull? Just thinking out loud.
 
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Old 06-04-2009, 09:22 PM
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I would look more into what you don't like about it. I don't have it but was told the cop bikes here in Las Vegas like theirs. I want ABS as I went down hard and would not have, had I had ABS. Good Luck
 
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Old 06-13-2009, 06:00 PM
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One reason I don't like it is that I have to "pump up" the front brake to get a good solid feel at the lever. There may be air in the system, I don't know. I've talked to a few Techs and they said it's inherent in the system, probably from the large volume of fluid being compressed as well as the valves in the unit. I can just imagine what it's like to bleed this plumber's nightmare of a system. I definitely need to get a shop manual for this bike.

Ideally, I would like to go to braided stainless lines like I did on my last bike. I learned to brake by feel a long time ago. Braking feel (feedback) is much improved with quality lines. I'm all about keeping it simple. I don't like the idea of just squeezing for all I've got and letting ABS handle the lock-up. ABS makes sense to me only on the back wheel, where lock-up is all but inevitabe.

And I want the rest of my saddlebage back.

Ride safe...
Cage
 
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Old 06-13-2009, 07:45 PM
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Originally Posted by Cage Dodger
...There may be air in the system, I don't know. I've talked to a few Techs and they said it's inherent in the system, probably from the large volume of fluid being compressed...
I'd certainly stay away from those techs - especially for the brakes - they seem to know nothing about hydraulic systems.

The (near) inability to compress a fluid is exactly why a fluid is used in brakes (and a few other systems). The multiplying transmission component of force is what makes a braking system work so well.



Originally Posted by Cage Dodger
...ABS makes sense to me only on the back wheel, where lock-up is all but inevitabe....
Actually the opposite is true. Most reasonably skilled riders can easily ride out a rear-wheel lock. In fact, the MSF folks teach this in their basic course to new riders.

But a front-wheel lock is all but impossible to manage. It's the front-wheel lock that lead to the development of the first ABS systems.
 
  #6  
Old 06-13-2009, 10:49 PM
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Originally Posted by Cage Dodger
One reason I don't like it is that I have to "pump up" the front brake to get a good solid feel at the lever. There may be air in the system, I don't know. I've talked to a few Techs and they said it's inherent in the system, probably from the large volume of fluid being compressed as well as the valves in the unit. I can just imagine what it's like to bleed this plumber's nightmare of a system. I definitely need to get a shop manual for this bike.

Ideally, I would like to go to braided stainless lines like I did on my last bike. I learned to brake by feel a long time ago. Braking feel (feedback) is much improved with quality lines. I'm all about keeping it simple. I don't like the idea of just squeezing for all I've got and letting ABS handle the lock-up. ABS makes sense to me only on the back wheel, where lock-up is all but inevitabe.

And I want the rest of my saddlebage back.

Ride safe...
Cage
As far as the "Pump Up" scenario.... You are probably used to a DOT 5 system... HD and Nissin had to use DOT 4 for this system, in a system that was originally designed for DOT 5... Both are good fluids, but DOT 4 has a "Spongier" feel than 5...

The way to tell if there is air in that particular system is to do an ABS event braking run....

Real simple... get up to 25 mph, grab the clutch, and hold (Not pump) the rear brake first, just like a car... then repeat for the front... If the brakes dont perform to the specs of stopping without locking up for a split second, there is air... There will ALWAYS be a moment when the wheel will stop to "Chirp" the tire, and release rapidly, or if you do not feel the pulses feeding back through the respective levers...

As far as bleeding it off, it is rather simple.. you let the pump do the work, and the valves route the fluid through the respective chambers...

As far as the saddlebags, got no response for that, as that is why the major change to the design of the FL Touring line happenned in 08, with the debut of the ABS for the mass'... That Nissin unit is HUGE, but well worth it IMO....
 
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Old 06-25-2009, 09:42 AM
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I have a mid-90s BMW with ABS and all the discs are as you describe. I would not be surprised if your system is a Bosch, the same as BMW used. I have never been able to make the ABS on that bike work, no matter how hard I try! It has ABS on both front and rear brakes and two of those bulky devices. I regard them as useless passengers.

Let's stand back for a moment. Every other model of bike Harley built that model year had a non-ABS system. So the answer to your question has got to be: YES! But to achieve that you should consider stripping every ABS related item off the bike and, if necessary, replacing it with standard stuff.

If the factory Parts List includes your model that is the place to start. It will, for example, show if your callipers and master cylinders are the same as all other models. If they are all you need is replacement hoses, as the discs don't need to be changed. Worst case is you need to replace both master cylinders as well as callipers, plus hoses. But the bike will be several pounds lighter!
 
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Old 07-02-2009, 03:45 PM
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OK, I bled the system, front and rear, and managed to get the old stuff out. (it was the color of slightly weak tea) I didn't see any bubbles come through, so I think it is just the nature of the system that it feels like warm crap. (rubber hoses everywhere and about 12' of extra line in the front)

Front and rear brake feel are improved, the rear more so as it got new pads too. The front still requires a double pump to get a good feel at the lever. Better than the two or three pumps before.

Just as a test, I unplugged the Nissin unit under the right saddlebag and rode it to see what would happen. Brakes worked normally (non ABS) but the ABS light stayed on. I don't see any way of getting into the tach to remove it but a friend gave me an idea. Get a wiring diagram and find the wire to the light and un-pin it from the plug. So that's probably what I'll end up doing.

The system stays as is for a while (I got other goodies I want, too) but eventually I want to replace the front left and rear rotors and don't want the $320 ones. The Nissin unit and any box hooked only to it will go as well as all that plumbing (and about 2 lbs of zip-ties). Replacing it will be new stainless braided lines. I bet that will improve things a little.

The most expensive part will probably be the right saddlebag bottom, unless I luck into a used one somewhere.

The only problem I see is that any time I take the bike in and they look at trouble codes, it may tell them the ABS isn't functioning properly, to which I'll reply, "No ****..."

Ride safe

Cage
 
  #9  
Old 07-02-2009, 03:56 PM
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Cage,

If you do scrap those rotors, I would be very interested in your old rotors. I am building a custom bike and want to see if I can use that ABS system. I know it sucks, but it is easy to work with. What I really want is the exciter ring that is rivited to the rotor.

Let me know ASAP. I have been looking for a long time and dont want to spend the $300 they want for that stupid rotor.

Thanks for the help!!

PM me or email me at racewurx@yahoo.com
 
  #10  
Old 07-02-2009, 10:03 PM
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raceworx....I may have a rotor with the ring...if I can find it you can have it, just pay the shipping. Cage you can take it off, we have done several, pm me if you need help.
 


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