5.75 volts

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I run a complete Commando points ignition on a Vincent. Because of the 50 degree crank, it never sees more than six volts at the points ( 12volt bike)
There is always one set of points closed. It uses the Commando six volt coils and makes very fat blue sparks at the slowest kickover speed.
It is the easiest starting bike I've ever had and those original Lucas points go forever.
Just don't replace the points with anything but real Lucas points, the Japanese replacements are terrible and will create problems.
55,000 miles to date on the same 2 sets of Lucas points.

Glen
 
L.A.B. said:
Deets55 said:
Yellow VOM is across ballast. Red VOM is across light. Not quite what I expected.
Click to expand...


The voltage drop (from both readings) isn't as much as what I would have expected either, and I think the reason is you are using a light bulb instead of a coil.

http://dylansautotronicsblog.blogspot.c ... colis.html
Click to expand...

Les,
Across the ballast is 1.214 volts, that is actually way more loss than I expected. I think I have a spare coil somewhere, when I get some time I'll give that a shot.
Pete
 
I'm late to this conversation, but it was my assumption that the lower voltage to a coil in a points ignition was to extend the life of the points because the points circuit is only triggering the coil's secondary winding, so it's voltage doesn't need to be 12volts, and since 6 volts causes less wear on the points and condenser, points systems reduce the voltage to the points.

I have a 69 ford that has a special "Resistance wire" that feeds power to the coil. If you measure the voltage at the coil, it's around 6volts. It was explained to me why it's done that way by a "ford guy". It made sense to me that the voltage drop is to extend the life of points which burn up twice as fast with a higher voltage.

I assume the ballast resistor does the same thing on our norton ignitions as the "resistor wire" does on my ford van... ?? I'm looking for a clarification of the reasoning I stated above. anyone??
 
Deets55 said:
Across the ballast is 1.214 volts, that is actually way more loss than I expected. I think I have a spare coil somewhere, when I get some time I'll give that a shot.
Click to expand...

1.5 (approx.) Ohm ballast resistor and 45W (I think, as no markings) headlamp bulb. Power supplied by my ancient Halfords battery charger.
5.75 volts


With 6V coil included, the headlamp looks bright but it's reflected camera flash.The bulb is very dim.
5.75 volts


Same, but this time measuring the voltage drop across ballast and coil.
5.75 volts


Ballast voltage drop, ballast and coil only, no bulb.
5.75 volts
 
I'm late to this conversation, but it was my assumption that the lower voltage to a coil in a points ignition was to extend the life of the points because the points circuit is only triggering the coil's secondary winding, so it's voltage doesn't need to be 12volts, and since 6 volts causes less wear on the points and condenser, points systems reduce the voltage to the points.
Click to expand...

That was a benefit of course but its my understanding it was in preparation for the Starter, the plan was for the ballast resistor to be dropped out of circuit when the starter button was pressed so the reduced voltage below 12V would be sent direct to the coils. The coils cope with this fine and produce a good spark, as soon as the starter button was released 6V was restored. I had a VW Golf MK1 that used this arrangement and never had to change the coil and it did 150K miles before I scrapped it.
 
o0norton0o said:
I'm late to this conversation, but it was my assumption that the lower voltage to a coil in a points ignition was to extend the life of the points because the points circuit is only triggering the coil's secondary winding, so it's voltage doesn't need to be 12volts, and since 6 volts causes less wear on the points and condenser, points systems reduce the voltage to the points.

I have a 69 ford that has a special "Resistance wire" that feeds power to the coil. If you measure the voltage at the coil, it's around 6volts. It was explained to me why it's done that way by a "ford guy". It made sense to me that the voltage drop is to extend the life of points which burn up twice as fast with a higher voltage.

I assume the ballast resistor does the same thing on our norton ignitions as the "resistor wire" does on my ford van... ?? I'm looking for a clarification of the reasoning I stated above. anyone??
Click to expand...



+1. Where did they hide that resistor? In my Mother in Laws '62 Galaxie it was under the dash about 2" from the ignition switch. Try and find that without an Internet search, especially if your a Chevy guy.
OP was asking why he only had 5.75 volts @ coil was the original question.
 
Danno I've had issues with 2 Boyers so Points are my next plan (after these 30 years). If I recall ...? condenser failed causing erratic running , but points always worked very well . Never had me push the bike to farmhouses for help (unlike Boyer Trigger diode failure and transistor pickup (the 2nd failure) after many years of riding). Should be easy to pack an extra condenser in tool bag. I do recall Lucas points to be far better quality to Japanese.
 
Deets55 said:
+1. Where did they hide that resistor? In my Mother in Laws '62 Galaxie it was under the dash about 2" from the ignition switch. Try and find that without an Internet search, especially if your a Chevy guy.
OP was asking why he only had 5.75 volts @ coil was the original question.
Click to expand...

On my 69 ford there is NO resistance fixture to operate as a resistor like many other vehicles have. Instead the old fords with points ignitions have a special feed wire to the coil which is as fat as a pencil and about 3 feet long which somehow has enough resistance to drop the voltage from 12 volts at the key to about 6 volts at the coil... I have owned many vehicles in the past with points. Only my van still has them. I'm planning on replacing the them with a simple "boyer-like" magnetically triggered electronic ignition by Pertronics which bolts right into the distributer in place of the points and eliminates all the points related headaches... I just messed with my van for 2 days only to find out I had a bad condensor... :x

If I was you, I'd put a pertronics unit in your mom's '62 galaxy. They install in 20 minutes using the stock distributor and I've heard good things about them.
 
Thanks all hopefully I'll get spark this weekend. Looking forward to hearing the old girl run for the first time in many years
 
PJFlynn said:
Thanks all hopefully I'll get spark this weekend. Looking forward to hearing the old girl run for the first time in many years
Click to expand...
Good luck I'm sure you will get it :D
 
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