Timing adjustment of the EFI and Ignition system as fitted to the bmw R11XX series bikes (1993-200?) by Frank Warner.
TDC means Top Dead Centre, when the piston is closest to the spark plug.
The information here comes from various sources; Haynes manuals, Bosch texts, web information,
some bmw information and other texts. I don't have one of these bikes!
It comes about from some corrections and information I provided on the adventure rider web site/board.
Blind leading the blind most of the time, but I do know something about the HES
and the Motronic system, so the R11 bits may be a bit iffy the other bits should be ok.
I welcome corrections, don't expect an immediate response nor a thoughtful courteous response
if I'm in an unthinking hurry. Sorry about that but I do have a full time job,
and like to go riding not making web pages. Have fun.
These timing checks and adjustments are very similar to the old points system checks.
A good deal of skill can be developed getting the point where the sensor is just changing over. Firstly - the basic choices
Using a timing light - probably the simplest method, but you risk your fingers if you decide to adjust
the timing with the motor running.
Using the bikes system - next simplest, you risk the coil (unless you disconnect it) and possible flooding
(unless you disconnect the injectors)
Using a test system - you have to build the system!
To check the timing of the electronic ignition, using a timing light.
The only speck you can reliable check is the idle advance of 0 degrees ie the 'OT' mark on the flywheel.
I do not know if other timing marks are present to check advance.
Also the amount of advance will change with engine speed and throttle position,
it may possibly change with temperature too!
The timing light must trigger off the HT (spark plug) lead.
connect the timing light up as per its instructions.
Start the engine and observe the 'OT' timing mark thought the timing inspection hole using the timing light.
This should be visible at idle speed. As the engine speed increases the ignition should advance.
Slowly rotate the motor
until the monitor just goes from a high to a low.
observe the flywheel position through the timing inspection hole.
If the timing is correct (at TDC) then the 'OT' mark should be in the middle of the hole.
To adjust the static timing of electronic ignition on R11XX series bikes (1993-200?).
There are three bolts around the alternator lower pulley one at the top, the others towards the bottom
that hold the HES plate. Loosen these bolts and rotate the plate until the monitor just goes from
a high to a low .
Tighten the bolts.
Some people have said that the timing can be changed using the BMW service computer,
possibly by entering numbers into the brain - I don't know.
I don't have an R11XX nor a bm computer so I could not say, other than it is technically possible.
However the brains timing is only as good as where the sensor plate is set.
The brain runs off that so it should be correct other wise the brain is getting false information.
The advance range is specified as 43 degrees - a particular large range - not much room for error.
If you want to change the timing then you can do so by changing the plate position.
Note this will change not only the ignition point but also when the injectors fire (not the duration or fuel quantity).
Some people have used a protractor on the K models and marks on the plate.
There are two options on the advancement
By angle - calculate the distance to move the HES plate and mark it out.
By angle - calculate the distance for the piston below TDC, then use a dial gauge to set the piston at that distance.
I'll leave the description of the first method for a later date.
I would use a dial gauge screwed into the spark plug, calculate the required distance
(if you know [or guess] how many degrees difference you want) using the formulae
Distance = (stroke/ 2 ) * (1 - cos(angle))
The stroke is the distance the piston travels from TDC to BDC - for the R1100 this is 70.5mm,
the units used here will determine the units the answering 'distance' is in.
Then rotate the motor to TDC as observed by the dial gauge either note the number or set the gauge to a reference position.
Now rotate the motor to the desired point as calculated from the Distance calculation and the TDC point on the dial gauge.
Then rotate the HES plate as described above in 'Adjust Static Timing'.
If you advance it too far then starting will become difficult, particularly when cold.
HES Background
The two hall effect sensors (BMW fix both of them on one plate) are located under the alternator drive pulley
(under the black cover on the front of the motor).
They are used to sense the position of the motor - so the Motronic brain knows when to do things.
If the plate is incorrectly positioned then the brain will do things incorrectly too.
BMW fixed the two sensors 180 degrees apart on the plate. I'm still confused as to why two sensors are used,
it would help to know how many cut outs are on the shield that interrupts the magnetic field.
At the moment I think one is used to determine TDC the other BDC, the second one helps
the Motronic determine the timing if the motor is changing speed rapidly. But I don't know for certain.
The Hall Effect Sensors used are compatible with Honeywell part No 2AV54 Search on www.honeywell.com/sensing/
This is available from Newark Electronics as part #96F1986 for around $us14.
Each sensor has a magnet on one side, the other side contains the hall effect device and some electronics.
The gap between the two is where a shield rotates, thus enabling the Motronic brain to determine
where the engine position is. The output of the device is 'open collector' meaning it is either 'shorted'
connects the output to the -ve lead or it is open circuit - depending on if the magnetic field reaches the sensor or not.
The actual hall effect thing has an output voltage that is proportional
to the magnetic field and the current through it,
all three of these components are orthagional (at right angles to one another).
That voltage is used by the electronics (inside this sensor) to determine if the output should be shorted or open.
Warning
Limit the time you have the ignition switched on as you may over heat your ignition coil if you take too long.
How long is too long? I'd limit myself to 60 seconds...
If you need to repeat the procedure wait for the coil to cool down, start again.
If your impatient put your hand on the coil, warm? If warm wait! It is your coil, your bike, so think, have a beer!
If your really worried by this then
don't do this procedure - leave it to a dealer
disconnect the coil primary wire - the Motronic will not be damaged doing this provided the wire does not
connect to chaise.
Don't use the bike to supply the power - disconnect the hall effect sensors from the Motronic and make a test jig. Someone is working on this idea. I'll let you know?
You cold flood the motor if you leave the injectors connected - disconnect them. If you do flood the motor you could damage the catilitic converter = $$$$
This information comes from various sources.
I do not have an R11XX to check things with so it is all from texts and my thinking.
It is worth what you paid for it. Maybe a little more.
Monitoring the Hall Effect Sensor
The follow ways can be used to monitor the Hall Effect Sensor
Using the bikes system and a voltmeter
Using a test jig
BMW use a test jig - basically this can be constructed from a battery
(9 volts is ok, or you could use the bikes battery), two resistors (720 ohm for the 9 volt battery say 1.2kohm for the bike battery)
two LEDs and some wire solder and some kind of connectors.
I'll let you figure it out for now! [I'll continue latter].
Using a voltmeter - well you will need to be able to distinguish between a voltage in the range 0 to 2 volts
('we' call this LOW) and a voltage in the range 2 to 12 volts
('we' call this HIGH) - a 20 volt range should be good enough.
Warning - damage possibility
You must connect the voltmeter negative lead to the chassis (and engine bolt should do).
The voltmeter positive lead needs to be connected to the HES output wire, either one should do.
The follow ways can be used to find the Hall Effect output wires
These can be found
under the front cover (alternator access) enclosed in a black plastic tube running from
under the lower alternator pulley upwards then back under the alternator.
Inside this tube should be a plated wire tube (screen) then inside that 6 wires - 2 black and 2 red, with another 2 green.
You want one of the green wires - which one does not matter too much.
The green wires change colour somewheres in the loom (I suspect at the connector) to orange (S1) and black (S2).
At the connector somewheres to the rear of the alternator? Should be 5 pin/sockets. This is an extension of the lead described in 1 just above.
At the EFI brain pin number 6 [black] or 23 [orange] (it does not matter which).
I'd go for No 2,but I have not tried it nor have I examined a bike closely so ... your choice!
How to rotate the motor.
Please rotate the motor only in the normal direction.
To do coarse adjustments
Rotate the rear wheel and the gear box in 5th gear.
Use the bottom alternator pulley bolt.
To do fine adjustments
Use the bottom alternator pulley and a long bar.
Possibly use the flywheel starter teeth through the timing hole.
Special Tools
The follow special tools may be required
A voltmeter - with a 0 to 14 volts (or unto say 20 volts) range. You need to be able to tell if the voltage is above or below 2 volts.
A rod - length 100 mm, diameter - I don't know but I guess from the Haynes photo about 8 mm diameter? maybe 6mm
A dial gauge - with a spark plug hole fitting
A timing light that senses off the spark plug HT lead.
Finding TDC
The follow ways can be used to find TDC
Use a dial gauge with spark plug fitting - fitted through the spark plug hole.
Rotate the motor untill the dial gauge indicates the piston is at the top of its position.
A rod - place through a hole in the clutch housing above the starter motor -
this area has a depression in the plastic to provide for the insertion of the rod,
some people use it for wiring = bad practice.
The 100 mm long rod should go through the flywheel when TDC is found.
I don't know what diameter the rod is but it looks 8 mm in the Haynes' photo.
This does have the advantage that the motor is locked at TDC.
Rotate the motor until the flywheel 'OT' mark is centred in the timing hole - the timing hole is located on the right - behind the teleleaver pivot, above and behind the cylinder.
An old school bm mechanic would use the dial gauge,
a modern bm mechanic would probably use the third method to roughly find TDC
then lock the motor using the second method and the special rod tool. Your call.
Me? I'd use the dial gauge if I could - this is independent of any manufacturing errors/tolerances and I already have one.
Finding the timing inspection hole
This has a rubber bung and is near the top rear of the right cylinder, to the rear of the teleleaver pivot.
Remove the bung and you are looking at the flywheel, there should be a mark 'OT' when the motor is at TDC.
