Ignition problem on my 500

SeeDoubleYou

Junior member
I seem to have a pot down on my 500 due to lack of a spark. I've checked the top end, coils, resisters etc.. and have moved down the loom. My question is this; is there a weak spot in all these gubbins? Do the Bosch units fail or is it more likely to be the minute wires that come up from the magnetic pick ups.

I was going to start with the pickups by doing some resistance and continuity checks. However the workshop manual doesn't seem to be much of a help. Can anyone perhaps tell me which combination on the 4-way plug relates to each pick up. Then I can make a start. If all is ok here then I guess I'm looking at the Bosch units

Thanks 
 
The pick-ups both have a white and white/black wire, one of the pick-ups has its pair marked with a red sleeve at both ends of the wires.  Continuity through the pick-ups should be in the 60-70 (64 iIrc) Ohm range.  But they seldom go tits up, it's their wires that deteriorate.  The pick-ups themselves are quite sturdy.  Push the sleeving back a bit, and chances are you will find the wire isolation crumbling.  With a little patience, a couple of metres of small guage silicon-sheathed cable and a soldering iron, these can easily be replaced to get the suckers working for a further 30 years.

Some aftermarket ignitions do away with the stock pick-ups, others don't. 

piet
 
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