Honda-SOHC
SOHC.co.uk Forums => CB500/550 => Topic started by: deltarider on March 05, 2021, 03:30:59 PM
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On p. 90 of the Shop Manual CB500-550 we find a coil test prescribed (see below). I don't quite understand Fig. 275 that shows three pointed electrodes. Why three and not just two?
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Explained here :) :-
https://www.themagnetoguys.co.uk/Spark-Test-Gaps
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I'm afraid I still don't understand. The ones next to each other, are they both Ground?
Anyway, this is how I've tested mine (be it statically!) the two plugcables facing each other sharing (and waisting) a spark. The black stripes are 7 mm apart. BTW, the white 'stripe' you see is not a spark, but a mere reflection of light. Has any of you seen that tester in the Honda fig. in real life/ Is it capable of testing dynamically?
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Not only seen one but used one in the 70's and the box had like a set of points so you had continuous sparking and a knob to increase the gap on the two contacts opposite each other till the spark diverted to the side one.
Hope that makes sense
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Thanks, Bryan. Was it a set frequency or could you vary?
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The three point tester gives you a more stable & reliable spark .. The third electrode does not have any electrical connection ... it just screws in and out. What you are doing is perfectly OK though ...you can buy 2-point testers similar to what you have made. Non of those take into account what happens under cylinder pressure anyway.
https://www.youtube.com/watch?v=zGaDzTigrgs
https://www.amazon.co.uk/Tester-Current-Briggs-Workshop-Equipment/dp/B077Q4KT3N
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From memory it was just a push button so probably set frequency but quite quick.
The tester box was part of the "required" tools for a UK dealer and did dwell, continuity, capacitance,voltage and the spark test. I think it ran from a 12v car battery we had to recharge but like i said this was early to mid 70's and a lot of water(and Guiness) has gone under the bridge since then
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Thank you, all. Intriguing, that third electrode.