Coils and resistors

[puffy75]

Without resistor cold crank 10.8 volts. 4000 RPMs 13.54 volts. These are the primary wire voltage readings without resistor. I wanted to measure this simultaniously with the Ignition Mate to determain spark (secondary) voltage but I found a weak battery will retest tomorrow after charging.

Fogey if you are getting a good ingition without the resistor I do not think you will damage the coils. I have seen many undamaged similar systems that do not have resistors. Honda uses this same system on many many models. I do think this was over engineered in anticipation of a problem that never occured. I think Honda thought these coils were going to get hotter than they ever do. It is like the clear rubber tube over the return spring on CB750 K4-K6. Was not needed but there it was.

[Entropy]

Well I have no idea what this means, but, I was getting 3 ohms on my GL1100 resistor.

Maybe it is the same resistor.

Odd. Beats me man. I do know that I don't have no 6V at my coils, they're getting full 12 with the resistor.

[Cookie]

You wonder if they expected these to go long distances and get very hot.
I'd probably run without the resistor at this point. I bypassed mine until I got the thing running about right and then I put it back.

[alwing17]

Randakk's tech tips has an excellent article explaining the purpose of the ballast on the 1000's. He states that the purpose is to extend the life of ignition components,primarly the points. Now those w/electronic(Dyna) on their 1000'suse a replacement or a piggyback resistor(depending on the age of the Dyna system)with the stock coils to reduce heat and premature failure of the coils. I also believe the resistor(s) on the Dyna system are used to reduce the voltage to the Dyna unit,and this is how the system was designed,so by running full B+ to the module and the coils,you run the risk of damage to the module and/or coils.
Think of this way...You have an electric motor designed to run on 120 VAC...If you hook it to 220VAC...Itt'l run,but for how long??? I have been experimenting w/different coils,and am currently running 2 GM DIS coils,w/a Dyna 3 system(the one w/the external module) I have seen where someone had posted on some website that they were using this set-up(not this one,I will try to do a search,and provide the link) and did not use any ballast resistor,and promptly fried the Dyna system in a matter of a few rides,I believe.
I am currently running both the stock and piggyback resistors on the Zonker,I do not know the voltage going into the coils when running(I will check today),but I have run this setup for @3000 miles,and no problems so far. The GM coils have a primary resistance of 2.4 ohms vs. the stock coils of 3.0 ohms. I did not know if this was going to pose a problem w/the Dyna system or not,and so far,it hasn't. I get an almost instant start-up,hot or cold,and much better driveability with this set-up...The spark will jump a1-1/2" gap,no problem,and have not seen noticeable wear on the plug electrodes,I did increase the gap to .035, though to compensate for the increased spark output.
Someone on the forum has the pics of my set-up on the Zonker that I sent them...Maybe if they see this post,they will post them.

[Old Fogey]

I disagree with the placement of a resistor to the primary lead of the coils. I want as much voltage as I can get from my battery to my coils. 12 volts thanks always. I have been running it that way for about 100,000 miles with no worries no over heated coils or ignition problems.

I would probably be the first to defend this but noooo. Not this one I think this is over engineering. No one as given me a good explanation for a resistor to the primary side of a coil. I believe it is the only Honda that has this. It does nothing for the points they are on the other side of the coil (main load) and protected by the condensor. Most Honda systems that are similar get a full 12 volts all the way through.

Maybe the test at Randakk's rally will prove me wrong but I think not.

Puffy, are you still running points on that 100,000 mile bike?
If so, what experience have you had with points problems ie. burning or pitting?
I've run many older bikes over the years with points and coils without resistors and not seen major problems with points pitting.
I can believe that there may be less with the reduced voltage across them but can't remember any undue problems with the full 12v going through them.

Just out of curiosity I had a look at other manufacturers wiring,
this one for instance from the Kawa Z650; points and coils, the diagram looks almost exactly the same as the Honda one but no resistor!

http://diagrams.kz650.info/wiring/images/KZ650-B1.jpg

[dwayne_hopkins]

Odd. Beats me man. I do know that I don't have no 6V at my coils, they're getting full 12 with the resistor.

Is that 12V with the engine not running? What are you measuring it with? There will be full battery voltage at the coils through the resistor, on the B/Y wires, until the spark unit fires. When the spark unit fires, it applies a near-short to the coil (12V drops to less than 2V in test on pg 15-5 in Honda GL1100 manual). This near-short in the spark unit allows the current to flow, and your voltage at the coil will drop to a value determined by the resistance of the resistor, coil, and spark unit. I do not know how long this near-short condition lasts, or if the duration varies with the engine speed; I doubt the latter since I do not see a "speed" input to these modules.

The voltage at your coil with the engine running will be a varying level voltage from B+ (V+) to the value determined by the resistance of the network. If measuring the voltage with a digital meter, you will likely measure a steady "average" voltage since they are slow response devices. An analog meter may allow you to see the fluctuation better.

Bottom line: removing the resistor will stress the coils on GL1000s and '82-'83 GL1100s more, and the spark units on '82-'83 GL1100s. Can the coils handle it? Most likely. Can the spark units? Don't know.

[puffy75]

Here are some readings I got yesterday.

Key off battery voltage 12.58

Key on, no fuse headlight, taillight. Battery 12.31 volts, primary voltage 11.46. With fuses 12.22 battery, primary voltage 11.21.

Cold crank no fuses, battery volts 10.55, primary 10.01 volts. With fuses battery 10.17 primary9.56 volts

Idle 700 rpms (Stevens tach) no fuse battery volts 13.89, primary 12.96 volts, spark voltage 12,000 volts. With fuses 11.07 battery volts, primary 12.52 volts? (battery must have charged up a little), spark voltage 12,000 volts.

4,000 RPMs no fuses, battery volts 15.47, primary 14.84 volts, spark voltage 12,000 volts. With fuses, battery volts 14.51, primary volts 13.51, spark voltage 12,000 volts.

All of the readings are without resistor.

I would like to point out that the stock 1000 coils have a 12V mark on them which to me indicates that they are 12 volt coils. I have never seen a coil for a GL1000 that has a 6 volt marking. I have seen 6 volt markings for 6 volt bikes. Never a 7 volt marking.

I like these test. I will look forward to the rally and the results.

Fogey to answer your question about the points: I ran points for 50,000 miles until I found the pointless ignition I wanted (Prestolite). I never ran the resistor and had the same set of points throughtout that time. Nothing was damaged. I just recently change the coils for the test result comparisons to Accel set I had. The stock coils are fine they just do not give the spark voltage of the Accels. The spark voltage is about 3,000 volts for stock coils with bike running. Both coils are capable of 40,000 spark volts. That is the meters highest reading. The Accel could produce more I suspect, the stock coils not much more.

[Cookie]

That's really interesting Puffy. I had been told that the stock coils did 7,000 volts over at the Honda shop.
What really counts is what you get on a running bike.

[Sagebrush]

Its entirely possible you have a bad resistor. Those big ceramic resistors can fail where the wire is connected into the resistor and will ohm out normally or near normal but when put under stress will not act correctly. They can also develop fine cracks in the ceramic material that under low voltage (i.e. that put out by an ohm meter) look OK but again will fail under load.

[Old Fogey]

There is a very (long) interesting discussion on the SOHC4 website on this subject, albeit mainly to do with fitting Accel or similar coils.

I can't pretend I understand even half of the real high technical stuff, electrics and electronics are not my forte, but it may be of interest to the experts here.

http://forums.sohc4.net/index.php?topic=30938.0

At the moment the carbs are off again and some of the ignition wiring is being redone, but once it's ready if it won't run with the resistor then it gets to run without it!

[LikeMike64]

Here are the pictures of AlWing17's set up, http://www.ngwclub.com/forum/viewtopic. ... 0&start=30 about mid way down.

[dwayne_hopkins]

Puffy, that sounds about right without a resistor, except the one higher reading on the coil. Yes, these are 12V coils, as stamped on them. As I understand, Honda ran them at lower voltage to extend their life. These were all on a GL1000, correct?

[puffy75]

Yes that is correct stock 1000 coils are 12 volt and I too believe Honda did this to extend the life but I think the resistor in the design was unnecessary. I also think that a higher spark voltage will come from a higher primary voltage. The readings I posted today were not stock coils. The readings I posted today were Accel coils, so all spark voltage readings are higher. They were on a GL1000 running voltage.

At Randakk's rally this year I will bring the Ignition Mate and anyone who would like can get a reading of availible voltage and running voltage for their bike. The comparisons will be great information to us all.

[dwayne_hopkins]

I'm looking forward to that, I would like to see how good my Accel upgrade is actually doing.

[78AZWing]

Correct me if I am wrong, but I understand that the resister in the Gl1000 is to keep the points from burning. Not the coil. It's a ballast resister, right?

But I am old and should probably have my medication adjusted again.