The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: flon3y on April 24, 2018, 09:33:31 PM
-
I recently purchased a 1981 R65LS and I'm in the process of diagnosing some ignition system problems due to intermittent starting. Fuel system checked out and so did air system.
So far I have tested the dual ignition coil and found improper resistances:
primary spec=.67-.77 ohm
primary measured = 1.7ohm
secondary spec = 3.7-5.3 K ohm
secondary measured = 0 ohm
The Ignition Module seems to check out okay by following the procedure specified on Thunderchild:
thunderchild-design.com/info-v2.html
The question I have is regarding the Ignition Trigger Can. Thunderchild specifies that the voltage should vary between a few millivolts and +12VDC, but I measure it at a few millivolts and +3VDC. The fact that it's alternating and generating a spark makes me believe that that it is functioning properly but the low voltage throws me off. I was hoping one of you more experienced owners could shed some light. I appreciate the help in advance.
-
Also I was considering buying the Dyna dual coil from BeemerShop as opposed to the OEM unit. It's far less expensive and appears to be a quality unit, are there any precautions with going this route?
beemershop.com/Merchant5/merchant.mvc?Screen=PROD&Product_Code=DC9-1_DynaBracket
-
Hello,
The HES is actually a transistor. As such, the power voltage is irrelevant because it is dependent upon the circuit the transistor is in.
There is another way to check the HES using a 9V battery and a led. The schematics is on this site but I've no time now to search it for you.
This device is useful to have lying around because you can use it for a static check when putting the bean can back on.
I'm very surprised by your secondary finding of 0 Ohm and your coil giving sparks. But these beast are capable of strange things.
Last but not least, depending on your ICU, the coil primary resistance is important. Too low and you overload the icu. Too high and the system is not optimal.
-
Also I was considering buying the Dyna dual coil from BeemerShop as opposed to the OEM unit. It's far less expensive and appears to be a quality unit, are there any precautions with going this route?
Hi there - I bought the dual coil back in 1996 after the new (3 year old) BMW coil packed up. I rode the bike for about 15 years before it was garaged - so I got a lot of mileage out of it.
.
I've been rebuilding the bike for the last 4 years - nearly finished - and have put the original Dyno coil back on as it was working well before the bike was taken off the road.
.
So although I have replaced much of the electrical equipment - upgraded alternator - diode board - rectifier - the complete Hall Trigger ignition internals - you get the idea - I am taking a chance on this unit - but by and large people report very long life from them.
.
-
You will hear many not only approve of but actually recommend the Dyna coils for our bikes. As Georgesgiralt said, you just need to make sure you get the correct one (ohms).
-
And here is the schematic for the Hall effect sensor. There is at least one recent thread here on the site where I asked a bunch of questions about these.
One thing to note, several have said that the switch is not a necessary part for testing the sensor
-
Here's a spec sheet for the Honeywell 2AV45 .
https://datasheet.octopart.com/2AV54-Honeywell-datasheet-92379.pdf
From the spec sheet, it shows .2-.4 vdc output voltage when activated .
-
So far I have tested the dual ignition coil and found improper resistances:
primary spec=.67-.77 ohm
primary measured = 1.7ohm
secondary spec = 3.7-5.3 K ohm
secondary measured = 0 ohm
Curious where you got the coil specs from. I would have expected a dual output coil for electronic ignition of that year to have a primary resistance in the region of 1.5 ohms so your measurement isn't that far out especially given how hard it is to accurately measure very low ohm resistances. The secondary spec seems odd too at less than half the value I would expected.
-
What ignition coil do you have ??
Black and gray, or black and red ??
Usually the secondary circuit is 11k-13k ohms for the OEM coils .
-
So far I have tested the dual ignition coil and found improper resistances:
primary spec=.67-.77 ohm
primary measured = 1.7ohm
The Correct resistance for this measurement depends on what coil you have
The original coil coil should be about 1.5 Ohms
later coils .7 ohms
secondary spec = 3.7-5.3 K ohm
secondary measured = 0 ohm
If "0" ohms is what you measured
That means it is "Shorted"
It would not even begin to spark
If you measured infinite it may spark but not for long
You could also have the scale set wrong on your meter
Another test on the coil is to test continuity between the secondary winding and the mounting tabs
It should read Infinite
The Ignition Module seems to check out okay by following the procedure specified on Thunderchild:
thunderchild-design.com/info-v2.html
The question I have is regarding the Ignition Trigger Can. Thunderchild specifies that the voltage should vary between a few millivolts and +12VDC, but I measure it at a few millivolts and +3VDC. The fact that it's alternating and generating a spark makes me believe that that it is functioning properly but the low voltage throws me off. I was hoping one of you more experienced owners could shed some light. I appreciate the help in advance.
The trigger when blocked with a strip of metal is outputting battery negative
So the voltage is relative to what voltage you are testing it with
So if you are using 12 volts to test it
Put a piece of metal in the trigger and leave it there
you should see approximately 12 volts between the center pin and the positive pin
If you are swiping the metal thru the trigger you will see a lower value because your volt meter cant respond quick enough
Dyna's are good coils get a brown 1.5 Ohm it will work with all the BMW ICU's old and new
I have tried all 3 different coils from .7 to 3.0 you will not tell any difference
The .7 ohm will just cause more heat in your ignition system and could burn out the early ICU's
-
Thank you all for the quick responses! The help is appreciated.
I pulled the spec from my Clymers manual that came with the bike. Now that I re-read it the specs I listed are for 'single coils' which at the time I interpreted as 'one coil per bike' not 'one coil per cyl. Either way my coil is shot with 0 ohms on the secondary.
My current coil is all black with a metallic bracket if that counts as gray.
-
The original coils were very prone to cracking
Sounds like that is what you have
This is how the Dyna mounts with the 90deg bracket
Make sure you do not short the terminals to ground or have them to close to the mounting bolts
-
Hello,
If you want to give a rapid trial, go to a car junk yard and search for an European petrol car. They very often have ignition coils with two outputs and primaries suitable for an electronic ignition system because it is the fuel injection computer that does the ignition ... It will cost you a penny or so and you'll have a coil very sturdy and perfect for the job.
It is possible that Asian or American cars use the same setup but I do not know them, so...
And do not look for a too recent car because they tend to use ignition coils into the plug connection like the latest bikes.
-
European vehicles that had this coil setup, have long since been recycled into scrap in the US .
From what I've seen of US manufactured vehicles, I have never seen an ignition module like the one that is fitted to our R65's .
The DYNA coil and adapter bracket are a plug and play set of parts .
Almost bulletproof .
-
I think George is refering to the coil not the ICU
When i was trying to use as much GM delco igniton and charging parts that i could
I tried to use a coil from a GM vehicle with my GM Delco HEI ignition module and it got very warm
It was only .7 ohm primary
It may have worked with a late version OEM Bosch ICU because they have current limiting built into them
I have not tested it so i can not recommend it
Currently I am using a 3ohm Green Dyna
It works just fine and the current load is low
Remember the coil has so much dwell time to saturate that low resistance coils just aren't necessary
-
There are some Harley coils which would work and I should think easy to find in the US.
-
There are some Harley coils which would work and I should think easy to find in the US.
Funny you say that because I thought the same
I had heard that older Harley's used this type of coil
In 2016 I broke down with a failed Dyna coil north of Indy
We had just passed a Harley dealer about 10 miles back and i thought they would have one for sure because of all the Harley's we see on the road
So I called them to make sure they have one
They acted like I was crazy because they didn't carry any older Harley parts
I was able to find a used coil at a little ATV repair shop and it got me home
One could also get 2 coils from an old Ford V8 and wire them in series like the points bikes had just to get you home
because it wont be pretty
-
Thank you all for the help.
I ended up replacing the coil with a blue Dyna (and bracket), put new plugs and wires (both were incorrect spec installed by the previous owner), adjusted the valves, adjusted the ignition timing , and adjusted the idle/mixture. The difference after all this is night and day, it's running great now!
I don't think the previous owner knew what he was doing with this bike which is funny given he provided me with Clymers manual that explained all of this...
-
You need the latest version ICU to use the blue coil
The blue coil has a primary Resistance of .7 ohms and can over heat the older ICU's
That is why I recommended the brown 1.5 ohm coil
-
Hi Mrclubike, is my Clymers incorrect in specifying the 0.7 ohm coil for an '81 R65LS then? When did the 'Later' ICU start being used?
-
is my Clymers incorrect in specifying the 0.7 ohm coil for an '81 R65LS then? When did the 'Later' ICU start being used?
Yes it is.
I don't believe a 0.7 ohm coil was ever used on an R65LS. You should have a 1.5 ohm coil as the very low resistance coils weren't introduced until 10 years after your bike was built. I'd either change the coil or carry a spare ECU of the latest type.
-
Hi Mrclubike, is my Clymers incorrect in specifying the 0.7 ohm coil for an '81 R65LS then? When did the 'Later' ICU start being used?
Yep
I told you to get a Brown coil :'(
Like Barry said get a later ICU if you do not know if it has not been changed
The later ones have a larger heat sink and wider bolt mounting pattern and require an adapter or a different bracket if you existing bracket is bolted on
Snowbum's website has very reliable information
Clymers can have errors
http://bmwmotorcycletech.info/ignition.htm
I have used 5 different coils and i could not tell any difference in performance
Only difference was the temperature of the ICU
Lower resistance = more heat
-
Your ICU bracket needs to look like this in order to use the new style factory mounting bracket for the later ICU
Here is the OEM bracket for the Later heavy duty ICU
http://www.euromotoelectrics.com/Bracket-Ignition-Module-BMW-R-61-31-1-244-832-p/ignmod-bracket832.htm
-
Some of the R65s have a welded on ICU bracket
Like mine
Cant use the above bracket with this
-
On the other hand, when my Crack'O Matic OEM coil died, I bought the current BMW coil (black with red spigots) and installed it.
Then I read my ICU will fail. So I bought a new OEM one.
Two years after and many miles more, the original ICU is still going strong.
But YMMV ...
-
If the 0.7 ohm coil works with older ECU's then that's fine but I would also be thinking about the fact that the ignition system could in theory be consuming double the power from the alternator and that the cables in the wiring harness are passing double the current they were designed for. I expect the later type of ECU manages dwell better to mediate the average current and heating effect. It would be interesting to measure the difference between them in this respect.
-
I have the original ICU on my '81 R65, the original black and gray coil quit in 1994, I replaced it with the later version OEM coil, the red and black, it failed in 2006 .
I've had a DYNA brown coil since then, at least so far, no issues with the ICU .
I ride in one of the hottest areas in the US .
-
On top of ICU heating the coil can be over heating also