Points
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Joined: May 2006
Posts: 50
Likes: 0
From: Delaware
RE: Points
hmmmmm.... let's look at this from a basic electrical "points" (get it?) of view... (sorry bout that).
Ignition circuit overview: Battery > key switch > kill switch > points > coil > plug wire > plug > engine block > frame > battery
The points system uses a set of contacts that make and break 12vdc to a coil, the coil then ups the voltage and sends it to the plugs. The spark tells you that current is flowing and that can only happen when there is a complete circuit (path). While the contacts are closed current flows through them. As they open the current must now momentarily flow through the air until the gap is so huge that current stops flowing, and that is pretty much what causes the "spark" you are seeing.
I converted my bike to an electronic iginition 14 years ago but if I recall correctly, a small (and I do mean small) amount of spark is a good sign. It should also happen every time the points "open" if my logic is correct. If it doesn't, then it only makes sense that the circuit is open (i.e. fouling plug, bad wire, flaky coil, dirty/loose connection) so you may want to give those items a quick look-see.
If the spark is huge, I'd look at the condenser (capacitor in electro speak), I am pretty sure that it's job is to keep that spark to a minimum so as not to "burn" the face of the contacts (points). If the contacts are blackened then current won't flow freely through them and you won't see the small spark you expect to see.
Hope this helps!
Ignition circuit overview: Battery > key switch > kill switch > points > coil > plug wire > plug > engine block > frame > battery
The points system uses a set of contacts that make and break 12vdc to a coil, the coil then ups the voltage and sends it to the plugs. The spark tells you that current is flowing and that can only happen when there is a complete circuit (path). While the contacts are closed current flows through them. As they open the current must now momentarily flow through the air until the gap is so huge that current stops flowing, and that is pretty much what causes the "spark" you are seeing.
I converted my bike to an electronic iginition 14 years ago but if I recall correctly, a small (and I do mean small) amount of spark is a good sign. It should also happen every time the points "open" if my logic is correct. If it doesn't, then it only makes sense that the circuit is open (i.e. fouling plug, bad wire, flaky coil, dirty/loose connection) so you may want to give those items a quick look-see.
If the spark is huge, I'd look at the condenser (capacitor in electro speak), I am pretty sure that it's job is to keep that spark to a minimum so as not to "burn" the face of the contacts (points). If the contacts are blackened then current won't flow freely through them and you won't see the small spark you expect to see.
Hope this helps!
Thread Starter
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Road Master
Joined: Aug 2006
Posts: 755
Likes: 43
From:
RE: Points
In regard to my question, it was a bad coil. It worked fine for 3-4 mins, seems when the coil heated up it caused the circiut to fail and killed the engine. Thanks for the help.
ORIGINAL: JAMES2
Any ideas on why my points might spark sometimes and other times notta?
I got fired up, it ran for about 4 min. and quit just like someone hit the kill switch.
Any thoughts?
Any ideas on why my points might spark sometimes and other times notta?
I got fired up, it ran for about 4 min. and quit just like someone hit the kill switch.
Any thoughts?
Tourer
Joined: Jun 2006
Posts: 459
Likes: 1
From: Florida
RE: Points
ORIGINAL: pittguy
Always replace points and condenser at same time,
Always replace points and condenser at same time,
That's good advice, but I had a time where the new condensor went bad twice before I found one that would last. I hate being a parts changer.
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Stage I
Joined: Oct 2024
Posts: 1
Likes: 0
1966 Harley Davidson
hmmmmm.... let's look at this from a basic electrical "points" (get it?) of view... (sorry bout that).
Ignition circuit overview: Battery > key switch > kill switch > points > coil > plug wire > plug > engine block > frame > battery
The points system uses a set of contacts that make and break 12vdc to a coil, the coil then ups the voltage and sends it to the plugs. The spark tells you that current is flowing and that can only happen when there is a complete circuit (path). While the contacts are closed current flows through them. As they open the current must now momentarily flow through the air until the gap is so huge that current stops flowing, and that is pretty much what causes the "spark" you are seeing.
I converted my bike to an electronic iginition 14 years ago but if I recall correctly, a small (and I do mean small) amount of spark is a good sign. It should also happen every time the points "open" if my logic is correct. If it doesn't, then it only makes sense that the circuit is open (i.e. fouling plug, bad wire, flaky coil, dirty/loose connection) so you may want to give those items a quick look-see.
If the spark is huge, I'd look at the condenser (capacitor in electro speak), I am pretty sure that it's job is to keep that spark to a minimum so as not to "burn" the face of the contacts (points). If the contacts are blackened then current won't flow freely through them and you won't see the small spark you expect to see.
Hope this helps!
Ignition circuit overview: Battery > key switch > kill switch > points > coil > plug wire > plug > engine block > frame > battery
The points system uses a set of contacts that make and break 12vdc to a coil, the coil then ups the voltage and sends it to the plugs. The spark tells you that current is flowing and that can only happen when there is a complete circuit (path). While the contacts are closed current flows through them. As they open the current must now momentarily flow through the air until the gap is so huge that current stops flowing, and that is pretty much what causes the "spark" you are seeing.
I converted my bike to an electronic iginition 14 years ago but if I recall correctly, a small (and I do mean small) amount of spark is a good sign. It should also happen every time the points "open" if my logic is correct. If it doesn't, then it only makes sense that the circuit is open (i.e. fouling plug, bad wire, flaky coil, dirty/loose connection) so you may want to give those items a quick look-see.
If the spark is huge, I'd look at the condenser (capacitor in electro speak), I am pretty sure that it's job is to keep that spark to a minimum so as not to "burn" the face of the contacts (points). If the contacts are blackened then current won't flow freely through them and you won't see the small spark you expect to see.
Hope this helps!
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From: Lititz Pa
coil
Cruiser
Joined: May 2020
Posts: 117
Likes: 44
From: Corrales NM
You need a meter. Don't be a parts changer. Your problem could be anything in the circuit even a loose wire. Fortunately it's a fairly small circuit.
You'll need a wiring schematic to save frustration.
mikeyhd is correct that the capacitor (condenser) is to reduce spark at the points when they open. In fact a bad cap will build
up the point material like a little pimple and is a good way to know if the cap is bad or you could test it if the meter has that feature.
Most don't but for few more $$ they do.
You'll need a wiring schematic to save frustration.
mikeyhd is correct that the capacitor (condenser) is to reduce spark at the points when they open. In fact a bad cap will build
up the point material like a little pimple and is a good way to know if the cap is bad or you could test it if the meter has that feature.
Most don't but for few more $$ they do.