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1Back to top Go down   Checking the timing of a K100 Empty Checking the timing of a K100 on Mon May 28, 2012 2:38 pm

ReneZ

ReneZ
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As referred to elsewhere I did some preventive maintenance and decided to renew my timing chain and look at the plastic guides and the timing chain tensioner as I had some rattling from the front at times. The bike has done about 85-90K miles and I was unaware if it had ever done before. I also took the opportunity to modify the tensioner somewhat, as BMW had modified the original one some time and fitted a piston like dish end on the spring. I ended up fitting a ballbearing ball that sat well on the spring, but didn't close off the plunjer.

I decided to take of both side covers to have a quick look at my rivets (6 rivet output shaft affraid ) as well.

Checking the timing of a K100 IMG_1989

Checking the timing of a K100 IMG_1988

I sprayed the cams with some dry teflon lube to ensure easy movement over the valve plates (I checked/adjusted clearance as well), tied the spark plug leads out of the way and took the spark plugs out (to be renewed) to prevent pressure build up whilst turning the engine over.



After I had removed the chain I compared old with new. One can measure length or measure difference between 'pulled' and 'pushed' links, but bending the overal chain slightly showed a good reason to renew.

Checking the timing of a K100 IMG_1987

The old one is the top one.

In order to be able to change the chain you had to remove the two gear wheels fitted to the cam shafts. For this (and further movement of the crankshaft) I fitted a ratchet wrench with an 8 mm allan key bit into the end of the shaft. Before removing the gear wheels I moved the indicator holes in the wheels to line up with the seam of the cylinder cover as per book.

In the UK you can hire some BMW tools from the UK BMW Club. Great service as some of these tools are not easy to come by and would see little use anyway.

Checking the timing of a K100 BMW%2520Club%2520Tools

In the picture you see the tools they can provide. The Hall sensor test box (9V battery inside LED indication), the sparkplug extension bit; basically a part to allow fitting of a dial gauge ouside of the spark plug lead pocket and a dial gauge.

Below you see the extender fitted

Checking the timing of a K100 IMG_2001

The new chain and 'modified' tensioner were fitted after counting the links; please look at the forum for further info! The timing chain cover was fitted, after clarifying if the new seal was to be soaked in oil or not (Not - thanks Forum!) BTW, a little bottle of Tylenol will be a perfect size for a guide for the new seal!

Checking the timing of a K100 IMG_2002

The ratchet was fitted, so we could turn the engine over easily again.

In order to be able to use the timing control box you need to connect it to the connector of the Hall sensors. This connector lies under the tank on the right hand side, connected to a plug that goes into the injection computer plug cover. With the tank pulled back its easy to get at. In the picture below you can see the plug against the tank

Checking the timing of a K100 IMG_2003

Below we have everything hooked up/fitted and ready to start the job. In order to understand how the hall sensor works a bit of theory (sorry Twisted Evil ) - BTW TDC means Top Dead Centre which is the point where the piston is at the top of the stroke/movement.

Our bikes have electronic ignition and fuel injection. In order for the engine to function it requires the right amount of fuel to be injected and the ignition to start at the right time. Lots of things to get right then! These are processes that are to be timed correctly with the revolutions of the engine and the way this signal is made available is through the Hall sensors. Sounds magical, but they are simplistically an on/off switch that switches when a bit of steel is put close to them or taken away. In the first picture you can see the sensor ring on top of the engine with the two opposing sensors (K100 - 4cyl 180 degr.). On the forward end of the crankshaft is a cup bolted that has an opening in its side, which is at the height of the sensors so that with every revolution of the shaft this opening (a little 'window') passes in front of the sensor, making it switch. This switching is used as a revolutions signal and to initiate the sparking of the spark plugs. There are two sensors and one window in the cup, so there will be two 'pulses' (on/off/on switches) per revolution of the crankshaft.Sleep Still with me here??

Gets worse Smile - They way an engine works is by burning fuel as you know. How it does that is important for the efficiency of the engine. I won't go into air/fuel mixture here, but I think all appreciate that you need to get the mixture right for proper burning (and thus energy generation) and emmision control.

To make the engine turn over you need to generate a pressure in the cylinder to push the piston away. You do this by burning the fuel, whereby the fuel is changed from a liquid (dense) form into a gas (expanded) form. You are generating a pressure build up every time you burn the fuel in the cylinder, which pushes the piston away and turns the engine over. However the speed that the pressure is generated over (the 'burning time' of the fuel) and the volume increase in the cylinder, once the piston starts moving away from TDC, need to be in sync. Basically meaning that you need to keep the pressure fairly high even when the piston is already halfway down the bore. This is controlled with the amount of fuel injected and the time it is ignited. The liquid fuel as atomised (lots of little drops) by the injectors doesn't burn instantanious when ignited. Its almost as if every drop needs to ignite the next one after the first ones are started by the spark plug. Its almost as if your looking at the rings in a pond if you drop a stone in it. This also means that you don't have instantanious pressure. Now we are getting to the reason of this little bit! This means that, in order that you have a correct pressure build up over the stroke of the piston you need to ignite the fuel before (!) the piston is in TDC. To make sure it happens at the right time (per book 6 degrees or .24mm before TDC) we need to put the piston at the right position of this .24mm before TDC and check that the indicator box light switches off at that precise moment.

Long story short; we have to set the ignition point at .24mm before TDC on cylinder No.1. We do this by means of the dial gauge and an extended pin, where the piston will push the pin out until it reaches TDC, before it is pushed back in once the piston moves past TDC. Further we have the timing box which will indicate to us when the hall sensor switches. Adjustment (if required) is done by rotating the sensor carrier disk clockwise or counter clockwise.



Checking the timing of a K100 IMG_2004

Found TDC and adjusted the dial to show '0'. The instruction book tells us that the initial setting should be 6 degrees before TDC, which computes to 0.24mm. You can see the black indicator adjusted to that.

Checking the timing of a K100 IMG_2007

OK, found the right position of the piston (.24 mm before TDC). Whilst looking at the indicator box meantime (Man can multitask!!) I noted that the light didn't switch at the right time.

Checking the timing of a K100 IMG_2008

In order to see if the sensor ring had to be adjusted cw or ccw I had to find the point where the sensor switched and then check the dial.

Checking the timing of a K100 IMG_2009

After a bit of playing around I found the right spot and fixed the sensor plate. I turned the engine over a few times in normal direction to make sure it was set right and job done!!

Possibly you have read the manual where it says to initially set the sensor plate with its hole lined up with the recess in the housing. I added the below picture to show you how the bike is set now so that you, with a simple 12V LED, can quickly check the timing. This is what you should see when the piston is .24mm before TDC. In other posts examples have been given how to make a timing check box, where CF's one with a 12V LED is very simple and possible to rig up road side with a bit of wire and the LED (I have a bit of wire with a 12V LED on the bike; easy for fault finding).

Checking the timing of a K100 IMG_2012



If you want to know a bit more about the operation of a 4-stroke engine please have a look HERE , where you'll find a better visual presentation than my piece above.

Further, if you have any comments, remarks, critisism on the above please let me know and I'll change/add to make sure it adds some value.



Last edited by ReneZ on Tue May 29, 2012 7:06 am; edited 3 times in total


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Greetings from Florida! Having a 'new' K  :cyclops:    Surprised-o: 

Rene


BMW K100 - 1985 (0030029) Checking the timing of a K100 Rain
BMW K1200GT - 2003 (ZK01223)
    

2Back to top Go down   Checking the timing of a K100 Empty Re: Checking the timing of a K100 on Mon May 28, 2012 2:57 pm

charlie99

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great set of pics and the process rene .

thanks


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cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OChecking the timing of a K100 Au-log10

'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
    

3Back to top Go down   Checking the timing of a K100 Empty Re: Checking the timing of a K100 on Mon May 28, 2012 8:30 pm

88

88
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Terrific pics and descriptions Rene....get that supper down ya, you've earned it! I'm enjoying this (and learning!)

88


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Checking the timing of a K100 Ir-log11 88....May contain nuts!Checking the timing of a K100 Ir-log11

"The world is a book and those who do not travel read only one page." - St. Augustine from 1600 years ago & still true!

Bike: K100LT 1988. 0172363. AKA the Bullion Brick! Mods: k1100 screen and stands.
K1: 1990. 6374189. Custom Stealth Black paint.
    

4Back to top Go down   Checking the timing of a K100 Empty Re: Checking the timing of a K100 on Mon May 28, 2012 9:27 pm

rosskko

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The last picture is a mirror.. I was admiring you photoshop skills with inserting an image in an image. Mirrors is cheats.

rossco

    

5Back to top Go down   Checking the timing of a K100 Empty Re: Checking the timing of a K100 on Tue May 29, 2012 3:17 am

nino

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Very nice work. Engine looks very clean. What oil you use, Rene?

    

6Back to top Go down   Checking the timing of a K100 Empty Re: Checking the timing of a K100 on Tue May 29, 2012 7:14 am

ReneZ

ReneZ
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@ Rossco - I used a mirror as I couldn't get the camera right in front of the sensor and I guessed most would use a mirror for the same purpose when doing a check/adjustment. What photoshop skills Laughing

@ Nino, - I'm using Castrol GTX 15W-40 semi-synthetic (A3/B3; petrol/diesel). I used Castrol GTX 15W-40 'High Mileage' before, but can't get it anymore.


__________________________________________________
Greetings from Florida! Having a 'new' K  :cyclops:    Surprised-o: 

Rene


BMW K100 - 1985 (0030029) Checking the timing of a K100 Rain
BMW K1200GT - 2003 (ZK01223)
    

7Back to top Go down   Checking the timing of a K100 Empty Re: Checking the timing of a K100 on Tue May 29, 2012 8:38 am

nino

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@ReneZ wrote:@ Rossco - I used a mirror as I couldn't get the camera right in front of the sensor and I guessed most would use a mirror for the same purpose when doing a check/adjustment. What photoshop skills Laughing

@ Nino, - I'm using Castrol GTX 15W-40 semi-synthetic (A3/B3; petrol/diesel). I used Castrol GTX 15W-40 'High Mileage' before, but can't get it anymore.

Thanks Rene. Now I am on shell 5 w 40, but I am thinking to change to 15 w 50, or 20 w 50. Summer will be over 30 deg

    

8Back to top Go down   Checking the timing of a K100 Empty Re: Checking the timing of a K100 on Mon Aug 20, 2012 2:53 pm

giles4060

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Hi ReneZ

Wondering if you could answer a query about the ignition box LED. in my K100 Clymer manual it states that the LED should go OFF when the timing is correct (assuming that piston is correctly positioned) however in the Clymer manual for my R80GS (R50/5 through R100GS PD) it states that the light should go ON when timing is correct.

Have kindly received the box of trikes from mike d and will do the job later this week. Just wanted to check the difference in instruction in the two manauals as the two bikes use similar systems.



Excellent write up and photos are very useful.


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Giles

K100 RS 1991
R80 GS 1990
    

9Back to top Go down   Checking the timing of a K100 Empty Re: Checking the timing of a K100 on Mon Aug 20, 2012 3:17 pm

mike d

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It should come on when the timing is correct.

Mike

    

10Back to top Go down   Checking the timing of a K100 Empty Re: Checking the timing of a K100 on Mon Aug 20, 2012 3:25 pm

giles4060

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@mike d wrote:It should come on when the timing is correct.

Mike

Thanks Mike.......I thought it odd that the two manuals for largely the same system state something different. That should save some head scratching later this week.


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Giles

K100 RS 1991
R80 GS 1990
    

11Back to top Go down   Checking the timing of a K100 Empty Re: Checking the timing of a K100 on Mon Aug 20, 2012 3:40 pm

Inge K.

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Just to confirm:

Checking the timing of a K100 Tennin10


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Inge K.
K100RS -86. (first owner), K1100LTSE -94.
    

12Back to top Go down   Checking the timing of a K100 Empty Re: Checking the timing of a K100 on Mon Aug 20, 2012 3:48 pm

giles4060

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Thanks Inge,

In my defence (as I have asked some daft questions on here) and so you know I can read.

Clymer BMW K Series 1985 -1997 Third Edition p69:

"14. With the engine at BTDC the diode on the tester should go OFF (I am not shouting they emphasise this with upper case). If the diode goes OFF the ignition timing is correct; proceed to Step 20. If the diode is still ON the ignition timing is wrong; proceed to the next steps"


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Giles

K100 RS 1991
R80 GS 1990
    

13Back to top Go down   Checking the timing of a K100 Empty Re: Checking the timing of a K100 on Mon Aug 20, 2012 6:43 pm

Inge K.

Inge K.
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@giles4060 wrote:and so you know I can read.
Then, we also have that confirmed.


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Inge K.
K100RS -86. (first owner), K1100LTSE -94.
    

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