The coil on my 98 Rat is dead

[Larry S]

I have power going in but nothing coming out. A new coil is $165. I have three or four Ace 100 coils. Will one of those work?

Larry S

[Bullfrog]

My guess is . . . no one has tried what you are asking about . . . so responses aren't popping up.

Ed

[thrownchain]

If you can figure out how to wire the Ace coil into the ignition circuit, you should be able to tell if you can get spark with any or all of them. Won't be a direct replacement, but should work. If you can't raise a spark off any of them, then maybe your problem isn't the coil.

[viclioce]

I haven’t tried it, but I can’t help but think an Ace coil shouldn’t be significantly different in output than a Super Rat. Both are 98cc in the stock config, right? So I would try it.

I did try an older Ace coil on one of my Road Toads and it did function. So I would think it should work, but it’s just an edjumacated guess. Victor

[socalhodaka]

Maybe it needs a repair, or call Greg. He probably has some used ones that work.https://www.youtube.com/watch?v=peofkWZDiDI&t=1s

[viclioce]

Kelly. I love watching this video! I have to do this for my Ace B coil because the spark plug wire is both hard & brittle. But I love watching it. Hope I do as well with mine! Victor

[Larry S]

I'm pretty handy with a soldering iron. I removed the electrical connections from the dead coil and soldered them to a known good Ace 100 coil. It worked, but the spark was not strong. I found a coil in my junk box that was almost twice the size of the Ace 100 coil. 37 mm x 42 mm vs. 43 mm x 65 mm. I have no idea what the larger coil came off of. I re-soldered the connections and mounted it. It works. I'm getting a fat blue spark.

I'm going to go with this coil until I can find a 98 Rat coil at a reasonable price.

Larry S

[gearyoliver]

The coil in a typical points ignition is constructed so that it converts a low primary voltage to a high secondary voltage and also helps store the energy. A CDI box builds a higher primary voltage and discharges it quickly. The coil doesn't store energy. Unless the coil specs match it could possibly damage the CDI unit. I'm not sure but it bears looking into.

[viclioce]

I don’t know if anyone else shares this opinion so I’ll ask.

It has been my experience that capacitors on motorcycle ignition systems simply work until they don’t. I haven’t experienced that a capacitor gets weaker and eventually fails. My experiences have been the capacitors work, then fail and stop working completely and immediately.

Does this observation stand true with others on this forum? I don’t believe that a weakened spark can be caused by a capacitor getting older. A capacitor stores energy and gives it all out on a single burst, similar to an electronic camera flash, which also uses a capacitor to generate a “Burst” of strong light.

Opinions??? Victor

[thrownchain]

True, it either works or it doesn't. Sometimes you can get an intermittent problem that it dies when it gets warm, but usually it just crashes.

[taber hodaka]

Over the years I have had few problems with condensers, I have had more trouble with points but a failing condenser will help the points burn. --------------Clarence

[dirty_rat]

Back to the original question - will an Ace 100 coil work on a 98 Super Rat? Probably not, as they are two different types of ignition system, as pointed out by gearyoliver. The Ace 100 system is a points system while the 98 Super Rat is a CDI system. You can possibly source another CDI coil that will work, like one from an early Honda Elsinore 125, etc., but even that you need to insure the electronic specs are within range.

[Tether]

Would one of these work? They claim it works on everything. I use one on my Bultaco points ignition and it works fine.

https://www.speedandsport.com/index.php ... tion-coil/

[viclioce]

It certainly lists enough different bikes, and says it works with points or CDI, &. 6 & 12 volt systems. Seems like it should work! ; D Victor

[thrownchain]

Certainly seems like it should. For $18 can't go wrong.

[Larry S]

The coil on Albert's "burned up basket case " thread looks like the same coil. Maybe he can tell us about it.
Larry S

[givergas]

all i know at this time is i had to do a little fabricating very easy and i solderer new connections on the wires coming from the magneto and condenser and got a new spark plug cap at the local auto parts store when all was hooked up got a healthy spark out of it, till i get the bike started thats all i can tell you ....albert

[viclioce]

Tether. I decided to give those coils a try! I bought 2 of them. I’ll put one on my Combat & the other on the Ace B I’m going to build for my nephew.

I am doing a rebuild on the old one I had for the Ace B. It was working, but the plug wire was hard & stiff. I guess the one I have is older because it seems the metal tab to which you solder the plug wire was much further back & deeper than the one used in Kelly’s demonstration video. But I should be able to complete the solder job and seal it with the gray RTV Cement. Victor

[fortunet1]

Back to the original question - will an Ace 100 coil work on a 98 Super Rat? Probably not, as they are two different types of ignition system, as pointed out by gearyoliver. The Ace 100 system is a points system while the 98 Super Rat is a CDI system. You can possibly source another CDI coil that will work, like one from an early Honda Elsinore 125, etc., but even that you need to insure the electronic specs are within range.

Interesting for this humbled new member here ...I found a coil under the plastic tank of my flat tracker Ace, but the latest Super Rat purchase from the museum... (rusty chrome tank)...I found no coil on it. it's going to be a slow learning curve...electronically ...for gramps here.

[viclioce]

I’ve been very successful at rebuilding the old coils. I’ve done several now. But, I’ve run out of plug wire and plug caps. Need to go out & buy more. Too damn cold & snowy to go out today. But when it clears & warms a bit, I have a Rat coil cut down & the plug wire removed, waiting for a new wire & cap. The blue & black wires appear to be fine. So just solder the new plug wire in place and add the new cap & it should be good to go! Kelly’s video shows how to do this easily & well! Give it a try!!! Victor