Hi, does anyone know what the resistance readings should be expected on my v50 Bosch electronic ignition, I have a manual and it only gives the expected readings for the pickups but I want to know the readings for the primary and secondary windings on the coil, also what readings should be expected on the amplifiers and on which terminals?. I have searched the web but have found nothing. The reason being I had a problem with the pickups which is now sorted but I wanted to check out the rest of the system. Cheers Chris.
Chris, could you share any stuff you have on the mk2 system? I have been emailing Cliff Jefferies in Oz to see if he is interested in developing replacement unit. He needs some leg work done and I am starting to look into it. I need to get hold of some electronic tools eventually but for now any bumpf I can read up on would be good.
Unfortunately not as simple as “resistance tests” on the amplifier(s), needs a test rig or actual system to run in, then look at the signals. Unfortunately you then need to know what you are looking at.
Coils’ windings can be resistance tested, but then you need the manufacturer’s data to compare it against to know if it’s within correct range or not.
That was my question, as there doesn’t seem to be any manufacturers specifications available, I think I will test several good coils I have and see if the readings are similar and take an average reading.
Do you know what sort of symptoms a faulty amplifier gives, or does it just not work if its faulty? cheers Chris.
As a guide I would expect an ignition coil primary to sink about 4 Amps ~ the HT secondary should be able to make a spark that will jump at least a quarter inch air gap, up to 1 inch.
For what it’s worth I have just resolved an ignition problem on my 1979 mkII. After rewiring everything I could not get it to fire up. Just the odd backfire. When checking though all connections i decided to see if I had blown the ignition boxes. I took off both from the bike, connected a resistance meter to both just to see if there was a difference between them.
5 terminals in 2 rows, with the negative lead on the connection that goes out to the coil (top of the 3 in a row, on its own) I got the following resistance readings: Adjacent terminal (middle of 3) = 15k ohms, Earth connection (bottom of 3) = 4k ohms, bottom of the 2 in a row was 400k ohms and the last one in the pair was 40k ohms.
Because both produced the same readings I decided both were good, the problem was elsewhere, it was, I had mixed up the 4 wires at the connection leaving the trigger sensors.