The Hodaka Club Forum

Hi everyone. Although I haven't posted for a while I check in every day and enjoy following all the topics. The first season with my B+ has been a little up and down... You may recall that it suffered a seizure back in May but since that she ran great for about 400 miles. Then the small end bearing tossed its needles so I replaced the top end again. And she never ran better until a week ago last Monday on my way to work when it lost spark.

With the flywheel off I noticed a bit of bared insulation on the wire between the exciter coil and the condenser. It appeared it might have been touching the felt pad bracket. I rerouted the wire and covered the damaged area with shrink tube. And the bike ran, first kick. All was fine for about a mile and half of test riding; spark lost again and a long push home in the dark. Once home, the bike started again but ran poorly, missing and would not rev past about 2500-3000rpm.
And since then --- Points are new and gapped to .013" I replaced the condenser and took the opportunity to locate it beside the secondary coil.
I replaced the secondary coil because the original seems to be oozing some gooey substance from around the HT lead. There is no kill switch and I've unplugged the main switch for testing. The exciter coil resistance seems to be on spec, around .8 ohms.

And here's what I've got---

The spark will not jump 3mm. Connected to a grounded spark plug it sparks intermittently. A full kick through produces only three or four sparks and not uniformly spaced, very haphazard.

My question is can anyone say if this sounds like an exciter coil failure?
I've changed lots of exciter, (or source coils as Yamaha calls them) on cdi type ignitions and the general symptoms are either complete loss of spark or good spark cold, failing when hot. I've not seen one go weak and intermittent like my Hodaka seems to be doing.

thanks,

Ken

Ken, could there be an intermittent complete short circuit in the setting of an electrical "leak"? Might be time for a detailed inspection of the magneto wiring, rotor, and ignition system. Also, it can be useful having someone kick the bike over in the dark while you inspect for a short circuit. Sounds folksy, but it works.

Actually, it sounds like dirty points. I suppose it could be an intermittent open circuit, like a broken wire. Wouldn't be the first time a plastic coated wire was broken down inside where you can't see it. Sometimes called a wiggle fault.

Yep, the infamous "wiggle test" called for by all the manufactures these days. Its routine to see me with a lap top connected to atv's, outboards, motorcycles etc watching for changes on screen while yanking and twisting suspected areas of wiring harnesses.
The points are new and appear clean, well aligned etc. For the record I've tried another condenser in case my "new" one was a dud.
I don't mind buying an exciter coil but by the time it gets here our season will be probably be over. I'd like to put the bike away running well so I know next spring its good to go. But I guess a new exciter and I would have covered all the components; if I don't find anything else, IE wiring etc.
thanks for your input Jack,
Ken

I don't know if this would help, but I'd put a socket that fits the flywheel nut on a variable speed drill.

I'd put the drill on the flywheel nut in this fashion and spin slowly when conducting tests.

With the plug "out" there's no compression, so you can observe the spark easily.

This won't solve your problem, but might make those try this and that then test easier.

The resistance of the exciter coil is noted in the Hodaka Workshop Manual. I don't have that with me now, but if you have that critical document you can check that value.

I did read about a bad exciter coil ONCE in the old yahoo Hodaka club site years ago. Guy named Phil Kitchem I believe reported this. Not much going on in this site now, but if it's still there you might " join" so you can look it up.

My guess, it's unlikely the exciter coil because of the ohms you report.

But I often guess wrong. Just ask my wife.

Hhhhmmmm has your wife been taking notes from my wife?

I rechecked the resistance and it does seem to be close to spec. My manual calls for .6ohms and I'm getting .8-.9 and when factoring in the meter leads its close. (DVOM with no way to zero the ohms meter; with leads touching it reads .2)
But today I brought my DVOM home from work that has a peak voltage adapter. With the secondary coil unconnected so the mag is "unloaded" each kick produces a wildly different output. One kick will be high 200's volts, the next much less than 100. I would expect it should produce well over 200 volts and of course should be relatively consistent.
Doing the same test loaded, (with the secondary coil plugged into the mag and a spark plug grounded on the cyl head) the readings are again variable and very low, from the mid 20s to just over 100 volts.
With an adjustable spark gap tester it starts out jumping 2mm, (obviously not enough) but after a few kicks will not even jump that gap.
I have uncovered the black and blue wires from the mag to the connector and all is fine. Conitinuity is good no matter which way I move or twist the wires so I'm pretty sure there are no hidden "opens" under the insulation.
And I checked the points resistance with 0-2 ohm "Yamaha Points Checker" and they test out to be as good as possible.
I from what you are saying exciter coil failures are rare and mine does seem to pass the resistance test but I think I've covered everything else. And I find the peak voltage readings to be far from acceptable.
Regardless I don't think having a new exciter coil would be a bad thing so I'm going to order one.

Ken

You can always rewind the primary coil. Don't know if it would end up costing less than a NOS or used coil, but it might serve curiosity to see if there is a hidden fault in the wiring. For example, there could be a bare spot on the windings that doesn't show on a low ohm test, but might show on a meg-ohm test, fault arising once it is generating a voltage. Might be jumping a gap inside somewhere that short circuits the output randomly.

Not to mention that it is cool to be able to rewind coils. Wire is available online.

I would try another set of points for the heck of it?? Clarence

Thanks guys. Clarence, this is on a second set of points since losing spark. And I tried two condensers.
Jack, I have rewound a lighting coil for my Yamaha DT400 making it a 12 volt system. But that was straight forward in that I went to larger diameter wire and wound as many layers as practical but I thought there was more to doing an ignition coil? As far as diameter and number of layers etc needing to be correct?

Something to consider for sure. But I may just "bite the bullet" and order up a new one. And then take my time and try to rewind the old one.
Ken

Hi Ken;

I would be hesitant to rely on a digital meter to record the maximum output voltage. These meters sample the voltage periodically and record the result. Since the coil output is AC, the voltage the meter reads would depend on when it sampled the voltage, and how often it samples (sample rate).

I have seen intermittent HV coils, wiring shorts inside the vinyl sleeving, and bad points (new sets), but I have not yet seen a bad exciter coil. Doesn't mean it can't happen, but I think it would be rare.

If you are ever down my way (near Guelph) I can probably dig up a coil for you.

Brian

I have to admit I don't think it is the primary coil at fault. I also don't think I have ever seen a voltage output reference for the primary coil. The comment about digital reading is interesting. I wouldn't have guessed that they sample voltage rather than read it, but then just use an analog meter which is more likely to give you an average voltage.

Try using the old, oozing secondary coil and see if that makes a difference. Somewhat curious to know how an epoxy potted coil can ooze anything. But, secondary coil failure is far more frequent than primary, and it is usually the spark lead. Have you checked the coil spark lead for failure? Seems to me Kelly has done a video presentation on how to rebuild the spark lead.

Lots of things to address so please bear with me.
Regarding the peak voltage readings - using an adapter many DVOM's will read peak voltage and this is a common test for CDI ignition components. For instance Yamaha, Mercury Marine and Suzuki, (brands we sell and therefore I work on) publish peak voltage specs for source, (exciter) coils as well as trigger, (pulser) coils. As well they have resistance specs of course. But sometimes I see resistances in spec but weak voltage outputs from these components. We always do both tests for diagnosis. And we check peak voltages unloaded and loaded as they sometimes can show good readings until they are under a work load - IE connected to the CDI, secondary coil and trying to jump a gap tester.
As far as how a peak adapter works here's a copy and paste I found to share ---
Some meters are capable of reading DVA or peak voltage pulses. Many ignition system
components produce short AC voltage pulses. A peak-reading analog meter or DVA adapter
plugged into a digital meter captures and holds the peak value of an AC sine wave long enough
for the human eye to see it displayed on the meter. A conventional meter is incapable of accurately
measuring these short-duration voltage pulses.
That explains it better than I can.

OK so can a peak voltage test tell us anything on an energy transfer points/condenser ignition system is the question. I don't know. We do so little work on these systems these days; the odd OMC outboard will come in but cost of labor and parts often makes repairs of old items uneconomical for the customer.
But--- I don't see why a peak voltage test wouldn't be useful? Even though I don't know exactly what voltage we need to fire the secondary coil it makes sense that the voltage should be fairly consistent. And my best guess is that it should be somewhere north of 150 volts? I expect 250 - 300 actually.

Of course all this is just experimentation; the bottom line is I still don't have spark after changing points, (which as mentioned are showing almost no resistance when closed and are opening to .013") and installing a new condenser, (plus trying another used one that was working) and checking the black and blue wires from the mag to the coil connection.
I'm not sure what the substance is that seems to be coming from around the HT lead; it might be that someone at some time in the past tried to seal the lead with black silicone (or similar) and that has warmed up and spread. The HT lead seems tight. Tonight I tried connecting it up and I got the same peak voltage readings as the other coil. And no change in spark. It will produce an intermittent weak spark with a plug laying on the cyl head but with an adjustable gap tester it will not jump 2mm.

I agree with everyone that an exciter coil failure would be odd especially when the resistance tests fine.
And I don't know if my varying peak voltage is an accurate test or should be concern at all. (although it does seem strange to me)
But I've changed and tried everything else in the system. Other than the flywheel which has good magnetism; it grabs and holds the key, nut, washer etc.

So moving forward I've ordered an exciter coil, another set of points and a condenser from Paul. Even it I don't need some (or any) of these parts this time they will be good to have in reserve.
I just don't know what else to try at this point. But over the weekend I'll play some more.

Too bad she quit so close to the end of our season...I only need 29 more miles and that would make an even 1000 for me and the Ace this year. That includes 1.5 pushing hahaha

Ken
PS- Brian, wish I lived closer. I don't make it to southern Ontario too often. But when I do I'll let you know and hopefully we can meet up.

"Regarding the peak voltage readings - using an adapter many DVOM's will read peak voltage and this is a common test for CDI ignition components...."

You realize of course that an Ace 100 isn't a CDI system. I would not draw comparisons with capacitor discharge systems and magneto/point systems.

Since you have ordered new parts, we can wait to see if these new parts change the equation. If they do, you win; if they don't, let us know.

Jack, for sure I'll update this topic no matter how my recent purchase goes. There is an answer here somewhere. It just doesn't seem to be one of the usual suspects.

Re points vs CDI system diagnosing: the next time I get an energy transfer system in the shop that is sparking I'm going to try the peak voltage test to see what the readings are. Just for fun.

thanks all,

Ken