bizarre Ignition Amplifier fault.

[Tony Smith]

Some people may remember that a couple of weeks back I bought a nice brand new heavy duty Euromelectic (or whatever it is called) Ignition Amplifier and the new mount to accommodate the much larger module. They might also recall that I also have a generic VW module made in Poland that I intend to try out and if all goes well, carry as an on board spare.

I've really got the irrits with this stupid ignition system lately, for some reason the last time I rode the R65 the advance/retard was sticking - I will fix that when I pull it all apart in the near future to fit a second hall effect so that I can have redundancy on yet another dumb way the thing can leave me stranded. I want 100% reliability because wifey and I are heading to a place called Longreach in June/July and that place is a bit remote.


Anyway, last weekend I decided to try my new Ignition Amplifiers - First the expensive EME one - NADA.

Thinking I might have just by chance got a dead one I tried the Polish generic one - also NADA.


Put the "old" Bosch Ignition Amp back in and the old girl ran like a Waterbury watch.


Now I accept that exchanging different modules just might make small alterations to timing, but not enough so that the bike would not start.

I had a bit of a think and decided that the only possible thing it can be is loss of one of the power feeds in the harness, which may not matter on the early module but may be important on the later one.

In any event I was too lazy to start trying to individually test continuity on all of the connectors in the 7-way socket so I simply ordered a new ignition harness from Moto Bins.

Does anyone see any fundamental flaw in the logic and, just to exclude some silliness on my part, can someone who has swapped the early module for a later one please confirm that there was no massive change in timing please?

[nhmaf]

Which model # did you get?  Some of them can be picky about the coil primary resistance - too low and they might go into overcurrent protection mode and not deliver the juice?  Some of the later ignition modules have difference advance curves for single & dual spark setups and need to be setup (I think) with the newer crank position sensors too.

[Tony Smith]

Which model # did you get?  Some of them can be picky about the coil primary resistance - too low and they might go into overcurrent protection mode and not deliver the juice?  .

I bought the current heavy duty module to suit the current edition of coil. I do not think I had any spark at all because even if the timing was horridly wrong it would have backfired given the fuel in the cylinders.
 
It remains a mystery, I will report back when the new harness arrives.

[Barry]

On the diagrams I've seen there is only one +ve feed to  the ignition module pin 4 on.

[Tony Smith]

Think I've figured it out - the later Heavy Duty EME unit and the Polish generic both have somewhat shorter and thinner pins than the older Bosch unit I am currently using, and the failed OEM BMW part - bingo I know what has happened.

The longer and fatter pins on the older units has forced the "receivers" in the socket a little lower and a little wider than they were originally with resultant loss of continuity on the power pin (at least).

I could probably fix it by planing a little off the top of the socket. But the rubber cover on the socket is split and I had to make an emergency repair on the power feed socket, so all in all a new harness is not unreasonable as the three pin power socket/plug combo will cost $10 and the cover for the 7pin JPT connector is $20 and the 3 pin JPT at the other end isn't all that flash either. Figure around $45 to buy all the bits to make my ignition harness pristine, not counting the hour or so to do it all, as against $60 for a brand new harness.

I'm cheap, but not that cheap!

[nhmaf]

Glad that you figured it out - I hate it when "equivalent" parts don't use the same diameter connectors!   Had that problem with a replacement trailer harness I installed last year..