Speedo wiring

[riceburner]

Have done a search, but couldn't find much of specific use, so - here's my question:

The digital speedo system on the Rockster works by a magnetic sensor (Hall sensor?) in the final drive box, the wiring runs up the rear brake hose, then around, through a 2-pin connector and into the rear wall of the fusebox, on the rhs.
Questions
1) where does the wiring go after it enters the fusebox?? without removing the fusebox, I can't follow it...
2) How does one remove the fusebox??

The bike has recently had the gearbox bearings, crown wheel pinion bearing and clutch replaced - so was totally to bits. The speedo is currently "flickering" - over a 25 mile ride this morning, the tacho recorded about a mile and half.

My thinking is that the sensor IS working, and IS sending the correct signals, but the Motronic (I assume the wiring goes to the Motronic box??) is not receiving the signal correctly. This (to me) indicates a crushed wire/poor connection somewhere (I've had similar symptoms when a disclock was resting on the wiring that fed into the fusebox wall).

Given the bike has been apart - is it possible that the wiring could be trapped somewhere between the fusebox and the Motronic?? If so, where is likely and how much do I have to take off the bike to find it??

[sweatmark]

1) where does the wiring go after it enters the fusebox?? without removing the fusebox, I can't follow it...
2) How does one remove the fusebox??

Burner,

Remind me: do you have ABS or not?

For ABS Rockster, the wheel speed ABS sensors' signal is modified by ABS controller (not the Motronic) and sent to speedometer via the ABS wiring bundle. Wheel sensors and speedo connections are twisted pairs for each. Don't think the signal paths ever enter the fuse box within the ABS-spec wiring harness.

For non-ABS Rockster, the BMW Electrical Schematic CD-rom shows direct connection between wheel speed sensor (we know it's rear wheel, though not specified in schematic legend) and the instrument module.



Close-up of the instrument module connections and wiring colors:



Here's the legend & schematic notes info:

R28 Rockster nonABS speedometer infos:

A9001 Instrument panel control unit
A9020 Flasher unit
B9210 Vehicle speed sensor
P9210 Speedometer
X9001 STVB instrument panel control unit
X9022 STVB instrument panel II control unit
X9210 STVB vehicle speed sensor
Abbreviations: "STVB" = Plug

If you suspect a wiring fault or intermittent connection for the wheel speed sensor wiring run, then you could install a jumper wire using twisted pair (e.g. from phone wire or CAT5) between the connector at rear subframe and instrument module.

I would check the connectors first, though.

You should not need to disturb the fusebox, unless there's a wiring fault within the main wire harness and runs through the box itself.

[riceburner]

1) where does the wiring go after it enters the fusebox?? without removing the fusebox, I can't follow it...
2) How does one remove the fusebox??

Burner,

Remind me: do you have ABS or not?

For ABS Rockster, the wheel speed ABS sensors' signal is modified by ABS controller (not the Motronic) and sent to speedometer via the ABS wiring bundle. Wheel sensors and speedo connections are twisted pairs for each. Don't think the signal paths ever enter the fuse box within the ABS-spec wiring harness.

For non-ABS Rockster, the BMW Electrical Schematic CD-rom shows direct connection between wheel speed sensor (we know it's rear wheel, though not specified in schematic legend) and the instrument module.



Close-up of the instrument module connections and wiring colors:



Here's the legend & schematic notes info:

R28 Rockster nonABS speedometer infos:

A9001 Instrument panel control unit
A9020 Flasher unit
B9210 Vehicle speed sensor
P9210 Speedometer
X9001 STVB instrument panel control unit
X9022 STVB instrument panel II control unit
X9210 STVB vehicle speed sensor
Abbreviations: "STVB" = Plug

If you suspect a wiring fault or intermittent connection for the wheel speed sensor wiring run, then you could install a jumper wire using twisted pair (e.g. from phone wire or CAT5) between the connector at rear subframe and instrument module.

I would check the connectors first, though.

You should not need to disturb the fusebox, unless there's a wiring fault within the main wire harness and runs through the box itself.

non-ABS bike.

So if I read that right... there's a direct link from the rear wheel sensor to the speedo unit itself? it doesn't go through the Motronic?
Interesting.
So how does the bike turn the indicators off after a set distance?? - Ah - I see a connection between the speedo and the flasher relay (or something). ok - interesting. Many thanks - that makes my initial error checking a bit easier.

Anyone know what sort of readings I should be getting from the speed sensor if I was to put a voltmeter/ohm-meter across the wires when the wheel is turning?? (so I can check the sensor is outputting correctly). (I have a digital multi-meter with various scales)

[sweatmark]

non-ABS bike.

Which should make things easy. Note that there are two part numbers for the Rockster instrument module depending on ABS status... I have assumed that the speedometer drive circuits are different.

So if I read that right... there's a direct link from the rear wheel sensor to the speedo unit itself? it doesn't go through the Motronic? Interesting.

That's the way it looks in the official electrical CD-rom. The Motronic doesn't care about vehicle speed. I'm sure the non-ABS wiring harness ties the wheel speed signal twisted pair into the main bundle that runs from (through) fuse box on left side of battery tray, and up to front subframe. Note that the potential rub points of the main harness are worth checking if you've got the tank off the bike:

http://r1150r.org/board/viewtopic.php?f=2&t=18580

So how does the bike turn the indicators off after a set distance?? - Ah - I see a connection between the speedo and the flasher relay (or something). ok - interesting.

Yes. I didn't include the turn signal flasher relay designation within info posted above, but there IS a connection from speedometer module back into fuse box and flasher relay.

Anyone know what sort of readings I should be getting from the speed sensor if I was to put a voltmeter/ohm-meter across the wires when the wheel is turning?? (so I can check the sensor is outputting correctly). (I have a digital multi-meter with various scales)

This is good question. Has haunted me since my ABS-removal and subsequent quest to make my Rockster's speedo work correctly. See my ABS Removal thread for background info.... which I need to revise when I dive back into the project shortly.

Quick answer: a new R1150** ABS front sensor should read 284.5 kOhms resistance on your DMM. Don't put any power through the sensor or you'll fry it and then see 1+ MegOhm resistance. I know because I zapped my Rockster's OE rear wheel sensor while experimenting with speedometer signal generation. Note that I'm assuming (1) the front and rear ABS sensors are of same type; and (2) the non-ABS bikes use the rear wheel ABS speed sensor.

Long answer: after much guessing, I conclude that the OE wheel speed sensors are passive, two-wire Variable Reluctance sensors:

http://www.instronics.com/sensoronix_variable_reluctance_speed_sensor.html

Before thinking much about the ABS wheel sensor setup (obviously not thinking, or wouldn't have fried my original sensors and had to buy a new part!), I figured that the sensors must be sophisticated units with integral digital signal processing for TTL output. That would be this type of sensor:

http://www.instronics.com/sensoronix_variable_reluctance_digital_speed_sensor.html

Both types of Variable Reluctance two-wire units are widely available, though BMW has their units custom-built for the R1150** (and R1100S and K-bike) applications. Never could find any documentation about the BMW sensors, nor the ABS computer for that matter, and I didn't have a scope to measure sensor signal nor speedometer input when I removed my iABS.

Recommend that you measure the rear wheel sensor resistance at rear subframe connector, then reconnect and measure resistance at the speedometer connector to confirm wiring continuity. Let me know your results.

[riceburner]

non-ABS bike.

Which should make things easy. Note that there are two part numbers for the Rockster instrument module depending on ABS status... I have assumed that the speedometer drive circuits are different.

So if I read that right... there's a direct link from the rear wheel sensor to the speedo unit itself? it doesn't go through the Motronic? Interesting.

That's the way it looks in the official electrical CD-rom. The Motronic doesn't care about vehicle speed. I'm sure the non-ABS wiring harness ties the wheel speed signal twisted pair into the main bundle that runs from (through) fuse box on left side of battery tray, and up to front subframe. Note that the potential rub points of the main harness are worth checking if you've got the tank off the bike:

http://r1150r.org/board/viewtopic.php?f=2&t=18580

So how does the bike turn the indicators off after a set distance?? - Ah - I see a connection between the speedo and the flasher relay (or something). ok - interesting.

Yes. I didn't include the turn signal flasher relay designation within info posted above, but there IS a connection from speedometer module back into fuse box and flasher relay.

Anyone know what sort of readings I should be getting from the speed sensor if I was to put a voltmeter/ohm-meter across the wires when the wheel is turning?? (so I can check the sensor is outputting correctly). (I have a digital multi-meter with various scales)

This is good question. Has haunted me since my ABS-removal and subsequent quest to make my Rockster's speedo work correctly. See my ABS Removal thread for background info.... which I need to revise when I dive back into the project shortly.

Quick answer: a new R1150** ABS front sensor should read 284.5 kOhms resistance on your DMM. Don't put any power through the sensor or you'll fry it and then see 1+ MegOhm resistance. I know because I zapped my Rockster's OE rear wheel sensor while experimenting with speedometer signal generation. Note that I'm assuming (1) the front and rear ABS sensors are of same type; and (2) the non-ABS bikes use the rear wheel ABS speed sensor.

Long answer: after much guessing, I conclude that the OE wheel speed sensors are passive, two-wire Variable Reluctance sensors:

http://www.instronics.com/sensoronix_variable_reluctance_speed_sensor.html

Before thinking much about the ABS wheel sensor setup (obviously not thinking, or wouldn't have fried my original sensors and had to buy a new part!), I figured that the sensors must be sophisticated units with integral digital signal processing for TTL output. That would be this type of sensor:

http://www.instronics.com/sensoronix_variable_reluctance_digital_speed_sensor.html

Both types of Variable Reluctance two-wire units are widely available, though BMW has their units custom-built for the R1150** (and R1100S and K-bike) applications. Never could find any documentation about the BMW sensors, nor the ABS computer for that matter, and I didn't have a scope to measure sensor signal nor speedometer input when I removed my iABS.

Recommend that you measure the rear wheel sensor resistance at rear subframe connector, then reconnect and measure resistance at the speedometer connector to confirm wiring continuity. Let me know your results.

ok - cheers for all that. Very useful stuff.

[riceburner]

ok - think I've figured this out.
it's NOT electrical.
It's Mechanical.

I had the main crown wheel bearing done last weekend, and the castellated ring that's mounted onto the spindle has come loose.
I can poke my finger down the speed-drive hole and hold the castellated ring stationary as I turn the wheel (by hand, natch!)

Anyone know how that ring is held on?? I have a manual, but it's only for the R1150R, which obviously doesn't have this speedo system (what BM's do?? R1100S I know has it - what else?)

I stuck a screwdriver through the speedo-drive hole and "levered" the castellated ring back onto it's chamfered mounting and it "seems" solid. (but obviously it's not). Span the wheel using the engine and the speedo acted normally! (and registered more than 20mph for the first time this week! )

Unfortunately - I think I'm going to have to have the drive box disassembled again in order to get this castellated ring mounted correctly.

[jfslater98]

You sure you want to do that yourself? Seems like the dealership that did the work is responsible for this problem, I would have them fix it.

[sweatmark]

I had the main crown wheel bearing done last weekend, and the castellated ring that's mounted onto the spindle has come loose.

Forgot about the differences between ABS and non-ABS for the wheel sensor timing!

Burner, does your rear wheel sensor point downwards into the final drive, from top down towards the timing ring? I've seen the OE parts diagram with that timing ring... how many segments does it have? The answer is of great interest to me!

Agree that whoever rebuilt your final drive should refit the timing ring.

I might have a good fallback solution for you, depending on the answer to the timing ring segments question.

[riceburner]

You sure you want to do that yourself? Seems like the dealership that did the work is responsible for this problem, I would have them fix it.

Nope - the independant will do it, I'm not going to.

I had the main crown wheel bearing done last weekend, and the castellated ring that's mounted onto the spindle has come loose.

Forgot about the differences between ABS and non-ABS for the wheel sensor timing!

Burner, does your rear wheel sensor point downwards into the final drive, from top down towards the timing ring? I've seen the OE parts diagram with that timing ring... how many segments does it have? The answer is of great interest to me!

Agree that whoever rebuilt your final drive should refit the timing ring.

I might have a good fallback solution for you, depending on the answer to the timing ring segments question.

As far as I can make out, and if I'm remembering correctly - it's 4 segments.
Do you know how it's supposed to be affixed??

[sweatmark]

As far as I can make out, and if I'm remembering correctly - it's 4 segments.
Do you know how it's supposed to be affixed??

Burner,

Afraid I don't know how the timing ring is attached to the bevel gear axle.

My formerly-ABS Rockster used the rear wheel's ABS ring, affixed via the rear brake disk cast bosses.

I'm guessing that there are 6 segments for the timing ring. If there's any way that you can confirm the number of segments, would be helpful in understanding the Rockster speedometer signal requirements.

There's a reason that the segment count for your non-ABS bike's timing ring is so important: I've confirmed my ABS-equipped bike's speedometer as requiring 100 Hz input signal for equivalent of 76 MPH. Considering the speedometer's built-in "factory error", the wheel rotation at that speed corresponds to a 6-segment timing pulse.

I've designed and had produced a new 6-segment timing ring that attached to the rear (or front) wheel brake disc bosses. If you're looking at significant cost to repair/attach the OE castellated timing ring, then I might have a good option for you.

[riceburner]

As far as I can make out, and if I'm remembering correctly - it's 4 segments.
Do you know how it's supposed to be affixed??

Burner,

Afraid I don't know how the timing ring is attached to the bevel gear axle.

My formerly-ABS Rockster used the rear wheel's ABS ring, affixed via the rear brake disk cast bosses.

I'm guessing that there are 6 segments for the timing ring. If there's any way that you can confirm the number of segments, would be helpful in understanding the Rockster speedometer signal requirements.

There's a reason that the segment count for your non-ABS bike's timing ring is so important: I've confirmed my ABS-equipped bike's speedometer as requiring 100 Hz input signal for equivalent of 76 MPH. Considering the speedometer's built-in "factory error", the wheel rotation at that speed corresponds to a 6-segment timing pulse.

I've designed and had produced a new 6-segment timing ring that attached to the rear (or front) wheel brake disc bosses. If you're looking at significant cost to repair/attach the OE castellated timing ring, then I might have a good option for you.

interesting.

FWIW the speedo behaved ok (I thought it was a little slow to pick up tbh, but it seemed to be reading correctly) this morning so with any luck I can at least hold off on stripping the box again for a bit.

I can check the segments again - it seemed to be 4 to me, but I wasn't actually counting - that was just the impression I got as I span the wheel.

Where on your bike was the speedo pick up mounted??

[sweatmark]

Where on your bike was the speedo pick up mounted??

For rear wheel ABS speed sensor is mounted into the final drive shell, below the rear brake caliper, and forward/above the centerline of rear wheel/axle. The sensor body is approximately 65mm in length and penetrates horizontally through the final drive shell, just outside the dimater of the bevel gear and big bearing. The sensor's active end protrudes about 10mm from the inboard surface of the final drive (behind the wheel central hub) towards the ABS timing ring that is affixed to the same cast bosses that mount the rear brake disc.

When the rear wheel ABS sensor is removed, an opening to the final drive's gear & bearing enclosure is revealed. The smell of sulfur anti-wear compounds from the gear oil confirms the opening.

The front wheel ABS sensor has a different shape and mounting arrangement compared with rear wheel sensor. The sensor's barrel length is shorter, and the mount uses two machine screws instead of one for the rear wheel sensor. Both sensors appear to be identical in construction, have same resistance when measured with Fluke DMM, and share connector types. ABS wheel timing rings are identical front & rear.

I believe your non-ABS bike has rear wheel (axle) speed sensor that protrudes into final drive casting vertically. Correct?

[riceburner]

Where on your bike was the speedo pick up mounted??

For rear wheel ABS speed sensor is mounted into the final drive shell, below the rear brake caliper, and forward/above the centerline of rear wheel/axle. The sensor body is approximately 65mm in length and penetrates horizontally through the final drive shell, just outside the dimater of the bevel gear and big bearing. The sensor's active end protrudes about 10mm from the inboard surface of the final drive (behind the wheel central hub) towards the ABS timing ring that is affixed to the same cast bosses that mount the rear brake disc.

When the rear wheel ABS sensor is removed, an opening to the final drive's gear & bearing enclosure is revealed. The smell of sulfur anti-wear compounds from the gear oil confirms the opening.

The front wheel ABS sensor has a different shape and mounting arrangement compared with rear wheel sensor. The sensor's barrel length is shorter, and the mount uses two machine screws instead of one for the rear wheel sensor. Both sensors appear to be identical in construction, have same resistance when measured with Fluke DMM, and share connector types. ABS wheel timing rings are identical front & rear.

I believe your non-ABS bike has rear wheel (axle) speed sensor that protrudes into final drive casting vertically. Correct?

yup - that's correct - it fits onto the flat surface on the smaller diameter section of the drive box.

[riceburner]

As far as I can make out, and if I'm remembering correctly - it's 4 segments.
Do you know how it's supposed to be affixed??

Burner,

Afraid I don't know how the timing ring is attached to the bevel gear axle.

My formerly-ABS Rockster used the rear wheel's ABS ring, affixed via the rear brake disk cast bosses.

I'm guessing that there are 6 segments for the timing ring. If there's any way that you can confirm the number of segments, would be helpful in understanding the Rockster speedometer signal requirements.

There's a reason that the segment count for your non-ABS bike's timing ring is so important: I've confirmed my ABS-equipped bike's speedometer as requiring 100 Hz input signal for equivalent of 76 MPH. Considering the speedometer's built-in "factory error", the wheel rotation at that speed corresponds to a 6-segment timing pulse.

I've designed and had produced a new 6-segment timing ring that attached to the rear (or front) wheel brake disc bosses. If you're looking at significant cost to repair/attach the OE castellated timing ring, then I might have a good option for you.

Mark - just FYI... I had to reset the speedo ring this morning (it came loose yesterday), and I counted up the segments for you. There are, indeed, 6.

[sweatmark]

... counted up the segments for you. There are, indeed, 6.

Burner, thanks for checking.

Here's the new timing ring I designed as replacement for the ABS bikes' OE part. The new timing ring has 6 mount holes for either ferrous or magnetic targets, depending on type of speed sensor to be used. Permanent magnets are installed in pics below:





The new timing ring will fit both front and rear wheels. My intent is to create a speedo signal solution for all the BMW bikes that use rear wheel speed sensors as source for speedometer signal, both the iABS bikes like my Rockster, and non-ABS bikes like yours, the R1100S, some K bikes. Front wheel installation of the new timing ring and a sensor looks most promising, since the OE BMW front wheel ABS sensor is spec'd for so many bikes.

If your castellated wheel speed timing ring in final drive becomes a problem, can send you a new timing ring for use on front wheel. I'm making final selection of appropriate sensor, and need to design custom mount adapter to fit the sensor onto fork leg.

[riceburner]

... counted up the segments for you. There are, indeed, 6.

Burner, thanks for checking.

Here's the new timing ring I designed as replacement for the ABS bikes' OE part. The new timing ring has 6 mount holes for either ferrous or magnetic targets, depending on type of speed sensor to be used. Permanent magnets are installed in pics below:





The new timing ring will fit both front and rear wheels. My intent is to create a speedo signal solution for all the BMW bikes that use rear wheel speed sensors as source for speedometer signal, both the iABS bikes like my Rockster, and non-ABS bikes like yours, the R1100S, some K bikes. Front wheel installation of the new timing ring and a sensor looks most promising, since the OE BMW front wheel ABS sensor is spec'd for so many bikes.

If your castellated wheel speed timing ring in final drive becomes a problem, can send you a new timing ring for use on front wheel. I'm making final selection of appropriate sensor, and need to design custom mount adapter to fit the sensor onto fork leg.

Could you not use the normal BMW front wheel ABS sensor mounting point?? I still have that lug on my front fork, the bike was non-ABS from the off.

[sweatmark]

Could you not use the normal BMW front wheel ABS sensor mounting point?? I still have that lug on my front fork, the bike was non-ABS from the off.

Burner,

Exactly what I'm thinking. I bought an extra front wheel ABS sensor to play with. Seems the OE part applies to many BMW bikes, so a speedometer signal solution that uses the front wheel sensor mount would solve problems for more folks than the rear wheel, for which there are several OE speed sensor configurations.

I'm working on two front wheel speed sensor options:

(1) Finding a small inexpensive magnetic proximity Hall effect sensor that will fit in the BMW's front wheel sensor mount, and using my new 6-segment timing ring as trigger; and

(2) Applying a PICAXE single chip computer and custom circuit board to massage the OE ABS sensor's output (with OE 100-segment timing ring) and provide the correct speedometer input signal.

I'm betting that our respective ABS- and non-ABS Rocksters use the same speedometer circuit board, with similar signal input requirements. Your bike's castellated timing ring produces 6 timing pulses per wheel rotation; my new 6-target timing ring is designed to do the same thing with appropriate sensor. Speedometer input experiments using 100 Hz signal to push the speedo to 76 MPH (which includes the BMW "designed" speedo error) confirm the 6 pulse/rotation setup.

Pics of the front wheel OE sensor and mount:











Will cut & paste this over to my original ABS removal thread when the job's done.