Heavy Duty Ignition Modules

[Tony Smith]

It's been a while.

After my last unpleasant little journey into the unknown I purchased three (3) more modules, One from Euromotorelectrics (although to be fair I emailed them and told them the one they sold me was faulty and they immediately sent another - they will be seeing my credit card again!, The 2nd came from China (also a HD module) and the third was a "standard" BIM 137 module, ostensibly a clone of what I have fitted.


The clone BIM 137 module fired up immediately on a warm engine and sat there idling.

The two HD modules would not start the engine, although unlike the previous two the spark plugs were firing, lots of backfiring etc.


And this get me to my question.

I have always understood that the BMW/BOSCH/Clone modules required no changes to timing. I think that I may be wrong and that relative to the original modules the HD modules are significantly retarded and would require a significant twist of the bean-can to start and run.

My question is - does this mirror the experience of anyone else who has gone from "standard" to HD Ignition Module?


Oh, and bye the way, the Bosch module remains fitted and the spare BIM 137 is in the rear stowage "just in case". Like someone else in this forum I don't detect the "standard" module running too hot even though the current edition coil is fitted and I can't be bothered re-timing just to fit the HD module - maybe in a year or so when I do the timing chain....

[georgesgiralt]

Tony,
I _do_ hope your Chinese modules would last longer than the one I bought !
It ran fine for less than 5 seconds and after that gave a nice blue smoke perfectly matched to the bike's color...
I decided for a little forensic on the ICU. And found something interesting. Could you find what on the pictures attached ?
The only advantage of these Chinese things is that they are really cheap !

[Tony Smith]

Is that a stray piece of wire on the removed cover?

Also pins 5 & 6 are nearly bridged by the very poor soldering.

A piece of coiled wire seems to have been used instead of a resistor, or is it simply a heating element :-).

I think I'll just keep buying Bosch 137s and leave it at that.

[georgesgiralt]

Good job! You've spotted the reasons of the fancy blue smoke !

[skippyc]

Just a thought, if the HD modules use lower resistance coils then the dwell time will be different which could change the timing.

[Tony Smith]

Just a thought, if the HD modules use lower resistance coils then the dwell time will be different which could change the timing.

I am developing a major hatred of the entire stupid ignition system adopted by BMW, I really am!

I'd need an oscilloscope to prove it but I *think* that the Bosch 137 module triggers on the beginning of the pulse from the bean-can, whereas I suspect that the HD modules trigger on the end of the pulse.

I think this because it is the only rational explanation, I'd just like someone who has gone from "standard" to "HD" modules to confirm for me.

Thing is, I'll bet nobody can because most of us only ever touch this stuff is there is a problem.

Somebody else is running the equivalent of the 137 module even though they have a late coil and frankly I think I will too. The HD modules I'll keep "just in case" and I'll carry a spare 137 and some heatsink paste for the time being.


But seriously - fit Boyer system to wife's "points" beancan in 1991 and never needed to look at it since - advance dealt with electronically so there is nothing in there but the trigger. Compare and contrast to the constant "niggles" we all seem to be having with ignition systems. I'd do it but for the amount I have invested in ICUs and the new coils.

[mrclubike]

For the record I still have not got the advance problem with the Emerald Island system I got from Ted Porter sorted out.
Even with the EI bean can I still only had about 20 deg of advance instead of the needed  26 deg.
So I had to unlock my old been can and run it with the mechanical advance and OEM ign module.
I may be looking for another brand of after market ignition system.

If you can shine your timing light into the bean can and see if the flash happens in a different place on the rotor with the 2 different Modules

[georgesgiralt]

Hello !
When I bought the new coil to replace the crack-o-matic, the local Guru said nothing to me except the wiring of the coil. He painted a + and N (noir, black) near the spades.
Then I read about the new coil very low resistance and the ICU having been modified.
So I asked him aout that. He said  to me that he has sold hundred of the new coils and never had an ICU failure. The only ICU he changed was because the bike started to burn due to a too rusty tank and the connector was destroyed. So, as I had already bought the new BMW supplied ICU, I kept it but as a spare. I have to say that the original OEM ICU does the job. The total bike consumption is around 10 A when ignition ON and then cuts down to about 2A in a few seconds. So overheating is not a problem.
I posted somewhere on this site the address for a Czech company making fine electronic ignition system fully programmable and with all parameters adjustable. This unit was used on a race Airhead and allowed them among other things) to win a classic race in France... So it works ;-) It could be a good solution if you need one ;-)
P.S. if you use a scope choose the probe with caution. These ignition system give very high voltage spikes and input stages of scopes are easily fried....