Ignition issue

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panhead_kicker
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Ignition issue

#1

Post by panhead_kicker »

I believe my bike is having an ignition issue. Stock 69 FLH. I'm having to dress the points very often, as opposed to a regular tune up schedule. Points are visibly sparking more than I think they should be. I've tried 1 old Delco condensor, 2 new old stock HD condensors (from 04 and 08), and a brand new Echlin condensor from NAPA. All seem to yield the same results, crappy idle/ run after a few miles. Bike can "surge". Each time I clean up the points and try a different condensor. And I've also put in a new set of points.
Voltage ~14.7v while bike is running. Spark plugs are pretty clean.
Any thoughts on what I may be missing?
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Mongrel505558
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Re: Ignition issue

#2

Post by Mongrel505558 »

"Any thoughts on what I'm missing?"

A Dyna S electronic ignition. The target disk mounts on your mechanical advance unit where the points cam would go, and the sensor, or pickup, place of the points. You may have to be creative with the mounting since the early shovel auto-advance timer doesn't have a removable points plate. There is the wire to the coil, plus one more wire to provide power to the unit. You can take that from the top of the coil, or whichever side you have your switched 12V wired to. If it fails (rarely does unless you short it) you can put your points back in on the side of the road. You have to get the cone shovelhead version because I don't believe they make one for the generator shovel, and when you static time it remember that your timer is spinning in the opposite direction from the cone shovel.

Or you can continue to chase down your points issue. Pitting and arcing points is usually a sign of a bad condenser, but you've gone down that road. Do you have a 3 ohm coil or a 5 ohm coil? Not sure that would cause your problem, though. It's got to be something simple (bad ground?). I have the same points ignition as you do on my '68 shovel and it works great. I use Blue Streak points for inline-6 Chevy (Nova, some Camaros) available at any good auto supply store. Are your points and plug gaps correct or at least close to correct?
panheadrider1961
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Re: Ignition issue

#3

Post by panheadrider1961 »

Coil condition ? Advance system when’s last time it was serviced. Check springs, Wallowed holes in weights by pins? Bushing on shaft egg shaped in breaker making gap go super wide when running , clean good connection at coil and point plate,,. Solder joint on terminals? Wire not cracked arcing ? Wire in tubing from coil to breaker to halt damage? Lots more to it than changing parts , good luck
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Re: Ignition issue

#4

Post by panheadrider1961 »

14.7 voltage is high 13.5 is normal battery reading when running at 1200-1500 rpm would look at regulator issue here .
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Re: Ignition issue

#5

Post by panhead_kicker »

panheadrider1961 wrote: Fri Jul 15, 2022 11:20 pm 14.7 voltage is high 13.5 is normal battery reading when running at 1200-1500 rpm would look at regulator issue here .
I did have to change out my mechanical voltage regulator last year for a new Dixie ( its internals did not appear as rugged as the old Delco) . Service manual calls over 15 volts an issue with the cutout relay...So its at the upper limits for certain. Not sure an extra volt would cause trouble at the points?
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Re: Ignition issue

#6

Post by panheadrider1961 »

coil should be about to start smoking with high voltage going to it ,it only will accept so much before damage it is not oil field like a car and the windings will get hot and crack coil body,if sending over the 3 ohms down the line to points thats way 5 ohms is needed for electronic trigger to throw energy to pick up to fire plugs , you may have to put in old style resistor looks like condenser to halt over charge at points
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Re: Ignition issue

#7

Post by panheadrider1961 »

and to add to you saying getting hot when riding, stop and has erratic idle sounds like coil overheat or damage has occurred and windings burnt
Mongrel505558
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Re: Ignition issue

#8

Post by Mongrel505558 »

panhead_kicker wrote: Sat Jul 16, 2022 4:52 am
panheadrider1961 wrote: Fri Jul 15, 2022 11:20 pm 14.7 voltage is high 13.5 is normal battery reading when running at 1200-1500 rpm would look at regulator issue here .
I did have to change out my mechanical voltage regulator last year for a new Dixie ( its internals did not appear as rugged as the old Delco) . Service manual calls over 15 volts an issue with the cutout relay...So its at the upper limits for certain. Not sure an extra volt would cause trouble at the points?
No, it won't. We're only talking a couple of volts difference from the regulator. The arcing across the points is on the order of thousands of volts, which is what it takes to ionize air and create a spark.

This voltage comes from the self-inductance of the coil. The spark coil is basically a transformer; with a low voltage primary winding connected to points/condenser/battery, and a high voltage secondary winding connected to the plugs/ground. When current flows through a wire it creates a magnetic field. If you want a big magnetic field you wind the wire around itself or an iron core many times in the form of a coil. Also, a changing magnetic field induces a current in a wire or coil.

When the points are closed a current flows through the primary circuit, setting up a magnetic field in the coil. When the points open the magnetic field in the primary winding collapses, inducing a much higher current in the secondary winding to the spark the plugs. It also induces a current in itself that wants to oppose the change in the coil's magnetic field, and the faster the change, the higher this current is. The almost instantaneous change when the points open induces a pretty big current through the coil primary circuit for a very short time, causing a big voltage across the points gap. A healthy condenser "absorbs" most of this excess voltage and suppresses arcing across the points. A bad condenser doesn't.

An ungrounded condenser or one with a bad connection to the points = no condenser. Everything looks healthy in the picture you provided. But with electricity you can't rely on looks.
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Re: Ignition issue

#9

Post by panheadrider1961 »

An ignition coil is a step up transformer. If 12 v is left on the primary winding, it will quickly heat up and burn. It’s an ohmic short circuit, and depends on inductive reaction created by AC or pulsed DC to limit current.
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Re: Ignition issue

#10

Post by panheadrider1961 »

The insulation in many coils can be damaged if output exceeds 35,000 volts. Once this happens, the coil's output voltage may drop causing ignition misfire when the engine is under load, or the coil may cease to put out any voltage preventing the engine from starting or running.
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Re: Ignition issue

#11

Post by Mongrel505558 »

panheadrider1961 wrote: Sat Jul 16, 2022 3:38 pm An ignition coil is a step up transformer. If 12 v is left on the primary winding, it will quickly heat up and burn. It’s an ohmic short circuit, and depends on inductive reaction created by AC or pulsed DC to limit current.
That is true, but the amount of time direct current should be allowed to flow through the primary circuit, while it should be minimized, still gives you enough time to kickstart your bike or static time your ignition.
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Re: Ignition issue

#12

Post by panheadrider1961 »

How many volts should a coil receive?
The voltage reaching the coil may be 12 volts , or about 7 volts if the coil has a ballast resistor . Most electrical equipment works on 12 volts. The coil in a ballast-resistor system is rated at 7-8 volts instead of 12 volts.
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Re: Ignition issue

#13

Post by panheadrider1961 »

and if riding pumping 14.7 volts to battery, wire from battery to positive side of coil also receiving same 14.7 volts storing higher voltage more than 3 ohms to as high as 6 ohms to blast points when they fire causing excessive arcing of points and rough running condition is this not the way it is set up ?
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Re: Ignition issue

#14

Post by panhead_kicker »

Mongrel505558 wrote: Fri Jul 15, 2022 8:18 pm
A Dyna S electronic ignition...
Currently on a mission.
Mongrel505558 wrote: Fri Jul 15, 2022 8:18 pm Or you can continue to chase down your points issue. Pitting and arcing points is usually a sign of a bad condenser, but you've gone down that road. Do you have a 3 ohm coil or a 5 ohm coil?
Stock coil
Mongrel505558 wrote: Fri Jul 15, 2022 8:18 pm ...Are your points and plug gaps correct or at least close to correct?
New points gapped to ~.020
Old plugs gapped to ~.030
panhead_kicker
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Re: Ignition issue

#15

Post by panhead_kicker »

panheadrider1961 wrote: Fri Jul 15, 2022 10:55 pm Coil condition ?
Both plugs are pretty clean. I'll pull the coil cover and check resistances, I've also got a spare to swap in.
panheadrider1961 wrote: Fri Jul 15, 2022 10:55 pm Advance system when’s last time it was serviced. Check springs, Wallowed holes in weights by pins? Bushing on shaft egg shaped in breaker making gap go super wide when running , clean good connection at coil and point plate,,. Solder joint on terminals? Wire not cracked arcing ? Wire in tubing from coil to breaker to halt damage? Lots more to it than changing parts , good luck
Admittedly, the advance stuff has not seen the light of day for years, but I'd say less than 15k miles. Connections look good and the assembly pretty clean. I may pull the breaker and go through if nothing else here shakes out.
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