Another coil problem

[alimey4u2]

Another quality thread for the archives....

[EMS]

I But there are rumours that some of these Accels measure 4.0-4.5 ohms, I think this is too much for our ignition system. If your coils measure 4.5 on the primary, I would try to contact the seller and ask if they could be returned and swapped for ones with primary resistance more in the desired range, I'd say 2.5 to 3.5 ohms.

See more here: http://accel.zn1300.com/

Awesome post, Juha Accel indeed offers coils with different resistance, depending on the application and it is important to use the correct ones.

[Juha]

I But there are rumours that some of these Accels measure 4.0-4.5 ohms, I think this is too much for our ignition system. If your coils measure 4.5 on the primary, I would try to contact the seller and ask if they could be returned and swapped for ones with primary resistance more in the desired range, I'd say 2.5 to 3.5 ohms.

See more here: http://accel.zn1300.com/

Awesome post, Juha Accel indeed offers coils with different resistance, depending on the application and it is important to use the correct ones.

Yes they do

They have at least 1.5 ohm coils for modern CDI ignitions, 3.0 ohm "for our bikes" and 5.0 ohm for HDs or so I believe

But what I understood from the kz1300.com article is that the 140413 coil, which is stated for 3.0 ohms, there have been examples of this exact coil measuring at 4.0 ohms or more... some sort of manufacturing issue

[Mike Nixon]

Great tips, Juha. I am compelled to add something. Although easy, resistance tests are the least conclusive, particularly where wire windings ("coils") are concerned. There could be a break, and a resistance test, since it does not load the coil, will not detect it. Best to use dynamic tests. The best is the oscillating box, a special tool. However, you can approximate the same results simply by attaching a battery to the coil's primary terminals. If you attach spark plugs to both secondary wires and provide a way for the plugs' metal bodies to connect back to the negative primary terminal, then each time the primary terminal is connected up (actually, each time the connection is broken, intermittently), the plugs will fire. Couldn't be any simpler.

About ignition coil primary resistance. It's best to not install an ignition coil whose primary resistance is less than the stock value, but only because that increases the current flow through the transistor inside the "spark unit." A tiny reduction in resistance, of say, some fractions of an ohm, won't probably do much harm however. The transistor is easily damaged in Honda's TPI (Transistorized Pointless Ignition) system. Even just starting the bike with a low battery can kill it (the transistor).

Primary resistance varies in aftermarket coils for one main reason. High performance ignition coils are simply coils with unusually high primary to secondary turn ratios. But a ratio has two parts, in this case primary and secondary. Either one can be altered to change the ratio. The secondary can get more windings, or the primary fewer, and in each case the ratio will get higher. Guess which is cheaper/easier? So traditionally aftermarket companies did it the easy way, by lowering the primary turns, which resulted in lower primary resistance than stock. This was okay in the day of points, because all that would happen when the resulting current flow increased was that the points would wear out sooner. But when transistorized systems appeared, this kind of high performance ignition coil could no longer be used, and the fussing and confusion over primary resistance began.

By the way, there are some folks using extremely low resistance ignition coils (under 1 ohm) on TPI systems presently. I would consider doing this highly experimental, that is, don't. It works but don't count on it working for very long. There are some reasons this may work, that are pretty weird and have to do with dwell time and so forth, but these folks are also finding that the usual warning about leaving your key switch on is even more deadly a problem with this setup. That is, you should never use your engine stop switch to turn off the engine and then leave the key on for an extended time, even on a completely stock system, as this is what overheats the ignition coils. Doing this with extremely low resistance coils is much more serious.

[EMS]

. There could be a break, and a resistance test, since it does not load the coil, will not detect it. .

Why does a resistance test not show that Wouldn't the meter indicate infinite resistance if a circuit wire was broken?

[Juha]

. There could be a break, and a resistance test, since it does not load the coil, will not detect it. .

Why does a resistance test not show that Wouldn't the meter indicate infinite resistance if a circuit wire was broken?

I think I can see the point in this -- and a good point it is. The amount of current that the multimeter uses is so tiny compared to the actual current when the coil is fed by the battery/ignition system

So if there is a break in the winding but the wire ends at the break are in contact with each other, this tiny multimeter current can pass through. But the much higher current from the battery has difficulties to pass through, at least reliably The same thing could happen if the soldering point at the terminal is cracked or broken.

[Mike Nixon]

. There could be a break, and a resistance test, since it does not load the coil, will not detect it. .

Why does a resistance test not show that Wouldn't the meter indicate infinite resistance if a circuit wire was broken?

Not necessarily, and that is the problem. The coil will expand with heat, i.e. use, and then go open. But it may, in many cases does, not expand when not loaded but just ohm'd, hence the reading could falsely be good, when in fact the winding is bad. This is in fact the classic problem with the CBX alternator field coil. But any coil has this potential for misreading, so pro techs do not use the resistance test. :) Besides, these old tech Kettering style ignition coils are so easy to test with a battery, and that test is so much more conclusive.

[Mike Nixon]

. There could be a break, and a resistance test, since it does not load the coil, will not detect it. .

Why does a resistance test not show that Wouldn't the meter indicate infinite resistance if a circuit wire was broken?

I think I can see the point in this -- and a good point it is. The amount of current that the multimeter uses is so tiny compared to the actual current when the coil is fed by the battery/ignition system

So if there is a break in the winding but the wire ends at the break are in contact with each other, this tiny multimeter current can pass through. But the much higher current from the battery has difficulties to pass through, at least reliably The same thing could happen if the soldering point at the terminal is cracked or broken.

Juha -- I wish I had said that! :) Precisely.

[korvette kid]

After employing all of the ideas from the " spark gods", and verifying that all of the checks were in spec., I discovered that it came down to a wiring problem that I finally realized after I went back to the basics. Haven't had a chance to ride it yet due to the spring snow strom passing through Colorado.

I would like to express my gratitude to all who responded to my problem with your excellent advise. What a great group.

thanks

[alimey4u2]

Good news KK.......

[bdento59]

See more here: http://accel.zn1300.com/

So, I see from the link that the KZ1300 crowd may be using Nology PFC-30D coils. Is anyone using Nology ProFire coils on their X, and if so how are you handling the mounting issue(s)? The Accel units look to be drop in (102mm C2C?), but the Nology coils appear to have entirely different overall shape and mounting hole separation. I'm OK w/ fabricating brackets, but if someone has already cracked this nut, I'm all for NOT reinventing the wheel. TIA.

[alimey4u2]

I use Dyna S green which are a direct bolt in to the factory mount.

[bdento59]

Is anyone using Nology ProFire coils on their X, and if so how are you handling the mounting issue(s)? The Accel units look to be drop in (102mm C2C?), but the Nology coils appear to have entirely different overall shape and mounting hole separation.

I gather that, from the sounds of crickets chirping and the results from the CBX club coils poll, that no one is using the Nology PFC-30D coils? What about their patented SP wires? Good stuff or expensive fufu dust? Opine away. TIA.

[EMS]

I don't know about the Nology coils. They make some special for Harleys and the ones for the KZ1300 I think are originally car coils . I went the Accel way with my KZ1300 and the CBX

[alimey4u2]

Dyna S Silicone with graphite cores here...