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FORCE RIDER

Abs issues

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FORCE RIDER

Hi.

As a new member to the Forum, can I ask if anyone has experienced any ABS faults on their machines?

I have warning light permantly on even when up to speed.

Sensors have been cleaned and the ABS ring has been checked and appears in order!

Any thoughts would be appreciated.

RideSafe

Force Rider

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Bigglesaircraft

Have you checked the gap between the ABS rings and their sensors.

Edited by Bigglesaircraft
Spelling again !!!!!!!

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embee

The few faults I can recall posted here have mostly been due to the slotted ring being bent for some reason (other bikes backing into them in parking bays etc). They are sensitive to varying gaps between ring and pick-up, the workshop manual gives tolerances, which I don't remember,  but it's of the order of 1mm gap so not much scope for error. Andym has given chapter and verse in other threads ..................

The other thing is the obvious connectors.

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FORCE RIDER

Thanks for the above, I'll do some searching of previous comments and double check everything again.

Best place to obtain a workshop manual?

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slowboy
On 13/02/2018 at 10:48, FORCE RIDER said:

Thanks for the above, I'll do some searching of previous comments and double check everything again.

Best place to obtain a workshop manual?

Honda dealers will sell you one, its about £40:00 and we'll worth it

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Andy m

If you can find a connector get a multimeter on the sensors. They should have a resistance (anything from 15 to 120 Ohms) and will make an AC voltage in the 0.3 to 2V range at 30 rpm wheel speed. Open circuit is sensor ****ed. No voltage with a spinning wheel is air gap. Lack of steady AC voltage is either a dinged polewheel, bearings ,or the fact your meter is a poor oscilloscope substitute even set to AC.

 

At this stage someone with an ODB reader or dealer diagnostics is your friend. You'll spend hours or days to find what a laptop will tell you in minutes. Plugs and cables are the usual issues.

 

Andy

Edited by Andy m
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Andy m

A small clarification, what seems obvious to me at breakfast may seem less so to a reader later.

 

You unplug the ABS sensor and check what output it makes, ignore any test signals the ECU is trying to send. An ABS sensor is just a huge coil of wire that acts like a little alternator. The sine wave of induced current is what it uses to check for change in the wheel speed.

 

Andy 

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Totally_Lost

@Andy m, I always thought ABS was something exotic stuff, but your way of describing on how it works, made me understand it right away. Thanks, you're a gifted man... :thumbsup:

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Andy m

Very nice of you to say so, I'm glad to help.

 

I had the advantage of working with a few of the people who did the first generation of electronic truck ABS. Dr Wolfgang Petersen in particular could draw things like the circuit (its all analogue at the basic level BTW) that converts the sine wave from the sensor to a square wave then adds it back on itself to give the rate of change of angle, all from memory. Now we have programmable stuff on top, but the basics remain. No speed signal, no so called traction help, nothing to stop the key fob turning off the engine, confused DCT....

 

The actual ABS is just a control loop. If wheel speed drops too quickly and is off the believable curve (developing this graph is the clever bit), hold the brake pressure and see what happens. If holding doesn't bring you back to the line release. When its back on the line end the function, let the driver apply whatever pressure he likes, see what happens. Repeat, repeat, repeat. Its a computer, it does if faster than you can read it.

 

Andy

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Rev Ken
3 hours ago, Andy m said:

Very nice of you to say so, I'm glad to help.

 

I had the advantage of working with a few of the people who did the first generation of electronic truck ABS. Dr Wolfgang Petersen in particular could draw things like the circuit (its all analogue at the basic level BTW) that converts the sine wave from the sensor to a square wave then adds it back on itself to give the rate of change of angle, all from memory. Now we have programmable stuff on top, but the basics remain. No speed signal, no so called traction help, nothing to stop the key fob turning off the engine, confused DCT....

 

The actual ABS is just a control loop. If wheel speed drops too quickly and is off the believable curve (developing this graph is the clever bit), hold the brake pressure and see what happens. If holding doesn't bring you back to the line release. When its back on the line end the function, let the driver apply whatever pressure he likes, see what happens. Repeat, repeat, repeat. Its a computer, it does if faster than you can read it.

 

Andy

Andy, I tried out BMW's prototype Maxaret ABS system at what was then called TRRL. I understood it was purely mechanical. Naturally it cycled far more slowly than modern systems, but it worked, much to my disbelief! Am I right that it was purely mechanical?

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Andy m

Yes, a flywheel with a set of weights like a scooter CVT. The weights controlled the valves.

 

38506901810_ec26721330.jpg

 

When the flywheel stopped suddenly the pressure was reduced so the flywheel spun up so the brakes reapplied so....

 

Developed for the Lockheed Constellation airliner in the 1940's.

 

A decent system, but I believe the flywheel had to be matched to the vehicle so a production engineers nightmare.

 

Andy

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Rev Ken

I thought you would know. Many thanks, we've moved on!

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