Regarding checking points resistance
Posted: Thu Nov 10, 2011 2:46 pm
First, thanks in advance to everyone again for continually providing me with great information.
There's something I don't understand about checking points resistance, and I'd really like to understand it. I'll get right to it:
I am under the impression that there's a way to hook an ohmmeter to my bike ('74 GT550) to test the points individually, so that when the point I'm testing is closed I get 0 ohms, and when the point I'm testing is open I get infinite ohms.
To the best of my understanding (which obviously isn't correct, is incomplete, or both) what I described above should be the case if I connect my negative lead to ground and my positive lead to the "inner" point (the one with the lead going to it).
When I do that, using the big ground strap for my negative lead, I do get 0 ohms when the point is closed, but when the point is open I get approximately 4.5-5ohms. I am forgetting the exact reading at the moment, but I think it's actually approximately the same reading I got when checking the primary coils, which seems like it's a clue, but maybe not. The battery is disconnected, ignition off, and run switch off when I'm doing this.
I guess what I don't understand is, with the points open, battery disconnected, and all ignition related switches "off", what is left to complete a circuit once the point opens. Right?
When I get the ohm reading above 0, this does align with the points opening visually and the timing marks, so it does seem that I'm getting the reading at the appropriate time.
So my question is, why I am not getting a reading of infinite ohms when the points I'm monitoring are open?
Thanks.
Andy
There's something I don't understand about checking points resistance, and I'd really like to understand it. I'll get right to it:
I am under the impression that there's a way to hook an ohmmeter to my bike ('74 GT550) to test the points individually, so that when the point I'm testing is closed I get 0 ohms, and when the point I'm testing is open I get infinite ohms.
To the best of my understanding (which obviously isn't correct, is incomplete, or both) what I described above should be the case if I connect my negative lead to ground and my positive lead to the "inner" point (the one with the lead going to it).
When I do that, using the big ground strap for my negative lead, I do get 0 ohms when the point is closed, but when the point is open I get approximately 4.5-5ohms. I am forgetting the exact reading at the moment, but I think it's actually approximately the same reading I got when checking the primary coils, which seems like it's a clue, but maybe not. The battery is disconnected, ignition off, and run switch off when I'm doing this.
I guess what I don't understand is, with the points open, battery disconnected, and all ignition related switches "off", what is left to complete a circuit once the point opens. Right?
When I get the ohm reading above 0, this does align with the points opening visually and the timing marks, so it does seem that I'm getting the reading at the appropriate time.
So my question is, why I am not getting a reading of infinite ohms when the points I'm monitoring are open?
Thanks.
Andy