As I've posted on LCGB site:
OK, update time....
So, Gary came over to mine and I set about putting the BGM retro coil/CDI onto my daily use orange Vijai. The BGM item looked of the usual BGM good quality so, if truth be known, I wondered if we would prove that the item was fine and that Gary's setup was somehow wired in wrongly.
I had taken the time that it was going to take for Gary to get here to go on line and find out all that I could. Something that was noted was that the early prototype CDIs had the colours GRN, GRN, RED, WHT but that the production item (as per Gary's) was reversed to WHT, RED, GRN, GRN... and that the 2 screw terminals on the top (+ and - on original points coils) were additional earth points that did not need to be connected.
So, we bolted the whole lot to the rear frame strut and checked that it was earthing body to frame, which it was, meaning that all was well if the item earthed through the body.
Wiring up as the production sticker suggested gave no spark, not even a weak one.
Attaching an additional earth to the top terminals did not give a spark either.
Reversing the terminals (in case the sticker was the wrong way for pre-production or production) did not give any spark.
Additional earths on the top terminals did nothing, again.
Then, just in case the manufacturer connected the terminals incorrectly when talking about the change from pre-production to production models, we tried swapping all colours but this did nothing either.
Before giving up completely I decided to take out the HT lead and to trim the end back slightly to ensure (100%) that the contact was good where it screwed into the top of the CDI, even though there was virtually no chance of this being the case. I had already made sure that the end of the HT that we had been trying against the frame for a spark (no HT cap or plug to give false readings) was cut back so no issues there. However, when I went to screw the HT lead back into the CDI it kept turning and not tightening up
Unfortunately, with only light finger pressure the threaded contact/spike inside the CDI had sheared through and the HT lead could no longer be fitted
This is not a case of over tightening as the HT lead never gave any resistance but just kept twisting.
Regardless of the fact that the contact broke off (something that has never happened to me before), this CDI simply didn't work when wired as marked and no permutation of connections resulted in a spark. To put it simply, the CDI didn't work. I feel for the suppliers of this item because the prototypes must have worked but it seems as though the production ones don't.
It should be noted that refitting the stator wires to my everyday CDI gave a healthy blue spark at low RPM by gentle kick-start use, showing that there is nothing wrong with my wiring, stator or any other part of the ignition system.
It'll be an interesting test to see how Gary gets on with returning this faulty item to the German supplier. When I asked him if he would ask for a refund or an exchange, he did say that a working exchange would be better than a refund as he still likes the idea (as do I) of these retro CDIs working.
Until the problems with these CDIs is solved, I'd suggest that people stick with their standard CDIs.
Adam