Ignition Cut Out after changing Coil

[Barry]

2. Measure the old Coil - 3.2 Ohms (if I'm doing it right?) - seems high compared to new one at 1.5 ohms

That's what I was getting at above.  

If the old coil is really 1.5 ohms and your meter measures it at 3.2 ohms

Then the new coil which measures at 1.5 ohms could have a real value that is much lower.

Do you know anyone with another multimeter that could check the measurements ?

If not there is another more accurate way of measuring the coil resistance.  Very briefly connect the battery to the coil with the meter in series set on the 10 A DC range and using 10 A socket.  Ohms law says you should get approx 8 amps. The new coil if it's lower than 1.5 ohms may damage the meter so I would try this with the old coil first and if it the current measures in the right ball park then you know it's a 1.5 ohm coil and not 3.2 ohms.   From the different primary resistance measurements I think you could then infer that the new coil is lower than 1.5 ohms.

[jonathanrowley]

George, many thanks, all helps me navigate the jungle I have obviously uncovered. The ICU references on the link earlier in the post as an OEM one.

I've just ordered a second one from EuromotoElectrics USA - looks like it's the very latest version ending in 284, heavy duty and should be updated to work with all coils from what I read.

I'm not sure about the Ebay one already ordered as:

1) its cheaper
2) cross references to different part numbers.

Either way in a couple of weeks I should have 2 chances!
For now the Bike is resting with New Coil and Regulator re-fitted.

Re the Old Coil - yes, its a bit knackered, looks like the frame has been hacked around, unknown origin and the middle was expanding with rust so time for it to go... despite the fact that it was running OK.

I just suspected it was ready for replacement. Can't see any part number on it, though it is a Bosch unit, so suspect it's original.

Will report back of course... cheers from the Desert

[jonathanrowley]

2. Measure the old Coil - 3.2 Ohms (if I'm doing it right?) - seems high compared to new one at 1.5 ohms

That's what I was getting at above.  

If the old coil is really 1.5 ohms and your meter measures it at 3.2 ohms

Then the new coil which measures at 1.5 ohms could have a real value that is much lower.

Do you know anyone with another multimeter that could check the measurements ?

If not there is another more accurate way of measuring the coil resistance.  Very briefly connect the battery to the coil with the meter in series set on the 10 A DC range and using 10 A socket.  Ohms law says you should get approx 8 amps. The new coil if it's lower than 1.5 ohms may damage the meter so I would try this with the old coil first and if it the current measures in the right ball park then you know it's a 1.5 ohm coil and not 3.2 ohms.   From the different primary resistance measurements I think you could then infer that the new coil is lower than 1.5 ohms.

Thanks Barry - I'm going to wait for some new ICUs then fit and retry!
Will report back but interesting reading.

[georgesgiralt]

Jonathan,
There is no link between the regulator and the ignition, except for the state of the battery ;-)
So you can put  the Euromotorelectric regulator back without negative influence (pun intended)
You can test the multimeter by setting it to Ohms , low range and short circuit the two measuring wires. If the meter is accurate, and of good sensitivity, you should read something in the range of 0.1~0.3 Ohm. Or less.

[mrclubike]

Snowbum basically says you have to use the latest ICU with the new Bosch ciols because of the low primary resistance they will burn up the old style ICU.
 That is one of the reasons a lot of people use the Brown Dyna coils (and they are cheaper and have a very good reputation)
http://www.euromotoelectrics.com/product-p/dyna-coildc2-1x1.htm
EME says their new ICU's will work with the new style Bosch coil
http://www.euromotoelectrics.com/Ignition-Module-BMW-R-12-14-2-325-284-p/ignmod-r284hd.htm
I think your old coil is from a K100 with the the ears cut off
http://www.euromotoelectrics.com/product-p/boigncoil-k513.htm

[jonathanrowley]

Jonathan,
There is no link between the regulator and the ignition, except for the state of the battery ;-)
So you can put  the Euromotorelectric regulator back without negative influence (pun intended)
You can test the multimeter by setting it to Ohms , low range and short circuit the two measuring wires. If the meter is accurate, and of good sensitivity, you should read something in the range of 0.1~0.3 Ohm. Or less.

Thanks George, New Regulator Back on - thought as much on reflection, just wondered if it was driving too much Current when the Bike was running.

Re Multimeter - it's cheap! Read 1 Ohm when shorted

[jonathanrowley]

Snowbum basically says you have to use the latest ICU with the new Bosch ciols because of the low primary resistance they will burn up the old style ICU.
 That is one of the reasons a lot of people use the Brown Dyna coils (and they are cheaper and have a very good reputation)
http://www.euromotoelectrics.com/product-p/dyna-coildc2-1x1.htm
EME says their new ICU's will work with the new style Bosch coil
http://www.euromotoelectrics.com/Ignition-Module-BMW-R-12-14-2-325-284-p/ignmod-r284hd.htm
I think your old coil is from a K100 with the the ears cut off
http://www.euromotoelectrics.com/product-p/boigncoil-k513.htm

Yep, that then now confirms exactly what has happened, new Coil burned out the old ICU - hope this helps others avoid similar issues!
Thanks!

[georgesgiralt]

I've read Snowbum article a couple of times. And, my OEM original ICU built for kick starter bike still survives the new BOSCH coil !
So I asked the local BMW Guru which is only dealing with airheads, from the 60's up to the last one, of the line.
He said he did not see any failing ICU AFTER replacing the coil for the new low primary resistance one.
So I think there is more than we know into these ICU !
this is why I noted the BOSCH P/N written on mine, and when traveling very far from home, I carry a spare coil (not from BMW, nor BOSCH) and a spare new ICU.
Jonathan, your meter reads 1 Ohm when shorted. So the actual resistance of the primary of the coil is 3.2 minus 1 equal  2.2 Ohm... Try to remove the corrosion from the spades and screws and you may well get the 1.5 one should read ...

[Tony Smith]

Snowbum basically says you have to use the latest ICU with the new Bosch ciols because of the low primary resistance they will burn up the old style ICU.

The above is what caused me to check the temperature of my nearly new BOSCH ICU. The results of the finger tip test lead me to buy a Heavy duty ICU from Eromotorelctrix (or however they are spelt) and a much, much cheaper "heavy duty" module intended for a VW.


You can imagine my annoyance and consternation when neither of the new ICUs would work in my 1984 edition R65. Careful thinking my way through the problem has led me to conclude that the older ICU modules have thicker and wider terminal pins than the newer type and that they simply may not make electrical contact with the terminals in an older 7 pin socket that has been "stretched" by the older variety ICUs.

My new ICU wiring harness arrived from Motobins last week and I did intend to fit it over the weekend, but I went riding instead, however a quick look at the 7 pin socket supplied by Motobins reveals a completely different type of connector and connection strategy. i am very confident that I have nailed the problem and will report back as soon as I have the new harness fitted and verify that my new ICUs suddenly work.

On the assumption that I am correct, then anyone with the older type ICU who is contemplating fitting the new HD ICU may also have to buy the new ICU harness.....

The other thing I promise to in the next week or so is fit the new (supposedly genuine made under licence) Chinese sourced 2AV54 hall trigger to one of my dead beancans. If it is likewise a success I will leave the Chinese device in place and rework another beancan to mount two 2AV54s so that a failure only means a few minutes delay to switch over the harness under the front cover. Fitting a second Hall effect looks like an easy task - I plan to use a rotary table to gain a high degree of accuracy, but I suspect that careful eyeballing would get it close enough to not matter.

[jonathanrowley]

I've read Snowbum article a couple of times. And, my OEM original ICU built for kick starter bike still survives the new BOSCH coil !
So I asked the local BMW Guru which is only dealing with airheads, from the 60's up to the last one, of the line.
He said he did not see any failing ICU AFTER replacing the coil for the new low primary resistance one.
So I think there is more than we know into these ICU !
this is why I noted the BOSCH P/N written on mine, and when traveling very far from home, I carry a spare coil (not from BMW, nor BOSCH) and a spare new ICU.
Jonathan, your meter reads 1 Ohm when shorted. So the actual resistance of the primary of the coil is 3.2 minus 1 equal  2.2 Ohm... Try to remove the corrosion from the spades and screws and you may well get the 1.5 one should read ...

Oo the plot thickens - I think it overheated, I felt it and smelt it - something to do with the new coil, as all was well before.
My new ICU ending 284 is on its way from the US and hopefully will be a plug in and go... we'll see.
Re the Old coil - I think it's knackered and on it's way to the bin.
The other Coil alternative looks interesting though if this doesn't work.

[jonathanrowley]

On the assumption that I am correct, then anyone with the older type ICU who is contemplating fitting the new HD ICU may also have to buy the new ICU harness.....

Be interesting to see, Snobum points to the ICU ending 284 being a universal later replacement for the earlier one.
Not sure what the date changes are..

Interested to here how you get on.

[jonathanrowley]

So, I received the new and updated ICU today and eagerly went to fit it to the Bike.

Once installed the Bike seemed reluctant to start, backfired a while, Banged a couple times then flooded and eventually stumbled into life. Flattened the Battery though so not quite right.

It works with the new coil, but now I'm wondering if the timing needs to be re-set?

Would the new unit have some sort of different firing profile?

I timed the bike with the old parts way back and I assumed it would be the same. It was spot on before.

Any ideas?
Battery flattened and now on charge, so can only retry tomorrow.

[jonathanrowley]

So charged the battery and fitted... couple of murmers and tried to fire but just turned over.

I took the front cover off and sprayed some wd40 into the bean can but no joy... where next with this plot?

Tony did you get any luck with the harness? Can you post picks, wonder if its a connector issue

Both iCUs pic attached - can see a slight difference in pins, tried squeezing connector up but still no joy?

[jonathanrowley]

Just to update those who kindly gave support, I conducted the paperclip test on the Ignition trigger connector and got a big fat spark - research points to the ICU and Coil being fine following this...

Not sure why it would have failed but maybe more ziggies from the new Coil and ICU pushed it too over the edge?

Feels like the butterfly effect really - one thing breaks another in this area. At least at the end of this I will have renewed the whole ignition system and it might last another 30 years!

Time for more modernisation.
I looked at various options - but a 2nd hand Trigger unit made no sense as it would be as old as the orginal - 1981 - i.e. it would be possible that it would fail again.

So I researched and landed on this Siemens unit from UK supplier Motorworks. https://www.motorworks.co.uk/vlive/Shop/Parts.php?T=5&NU=15&M=20&Ct=IA&SbCt=BA_15_20_IA_40

It looks good - and I used to work for Siemens!   So hopefully it will arrive and be the solution - will report back soon.

[jonathanrowley]

So to close this out for now, the unit arrived today and I fitted it the Bike this evening.

Bike started first time - very strong sparks - it's been an expensive path, but hopefully one that gives some peace of mind over a 1981 ignition system that was I think, creaking at the seams and could have failed at any time.

After researching it and getting the answers here the whole thing seems a bit of a kludge from BMW.

Neither as mechanically reliable as points nor as robust as full Electronic ignition. Strange decision by BMW Engineers...