Dyna Coil and Ignition issues

[HaggardnShoved]

Hey everyone,

Got a 90 FLHTCU Engine (stock) that I’m running a 2Ki ignition on, with an electric start. When I first built the bike, being me I had a 5.0 OHM Coil on there, riding down the road and she dies on me.

Now to my understanding a 5.0 OHM should read within .5 of 5 OHMs, it was reading extremely high at 9.0 OHMs. The 2Ki gave me a rapid flash and that alone let me know something had to have been up with the coil. That and I got no spark. (Running a 12V Battery and I’m getting 12V to the coil.)

Fast forward I just put a 3.0 OHM Coil on there, timed it, no rapid flash, timed just how it was supposed to. No spark. I still have 12V going to the coil. But NOW my 3.0 OHM is running at 6.0 OHM’s with an Output of around 17,500.

At this point I’m at a loss as I’m either frying these damn coils with the wrong size or it’s my ignition system. Which I don’t think is likely. Any input would be great.

[JBinNC]

Your ignition module should not be hurting the coils. The correct coil for a Dynatek 2000 is 3 ohms, so you have that right. There are a lot of poor quality coils on the market now. What is your alternator output?

Jim

[HaggardnShoved]

The bike won’t start so I can’t test to see if the regulator is draining. I get an OL reading for OHM’s on my stator and no voltage output whether it’s on or off so I know the stator is good, it’s also brand new.

When I tested the regulator for voltage I plugged both holes and got a zero. Also got an OL reading for OHM’s. When I ground it and test the voltage I get a 0.1 for both plugs.

Bad regulator? I mean that’s also brand new. But could it have been burnt out by running that 5.0 OHM at first? I’m at a loss.

[JBinNC]

The point I was trying to make is that if the alternator is overcharging, that might damage a coil (and possibly the module for that matter).

Jim

[farmall]

You can verify if the ground side of the coil is being switched on and off by the ignition to test the ignition.

Procedure is verify power to coil (which you did), then probe the ignition/ground side of the coil and rotate the engine to see if your test light goes on and off as the ignition makes and breaks the ground connection. You can do this with plugs out to save battery but you need to connect the plug bodies so the coil can fire across them. I tack weld any two tested good spark plugs together which is super convenient since it can dangle in space but a hose clamp will do.

If there is power to the coil but the ground side is not being switched then there's a connection or ignition problem. You can disconnect the ignition side then connect a jumper to the ground side of the coil and flick it quickly against the engine to ground and unground the coil which will produce a spark though often a weak one.

BTW I keep spare complete ignitions (EI and points) handy for my fleet which makes maintenance and "swaptronics" troubleshooting easy.

It shouldn't affect ignition but 12V is a flat battery and battery resting voltage should be considerably more. It varies by battery but Yuasa use 12.6v. If the starter turns the engine you're good.

The ignition and charging systems are separate of course so fix the ignition first then perform a running charging system test and halt if voltage is too high to avoid smoking the ignition. (If in doubt, higher voltage doesn't bother points and you can swap on the roadside. I carry a points setup with advance on long trips because an EI coil will live long enough to get home, though I've thought about carrying a ballast resistor and will test adding one to an EI coil one day for shits and grins.)

Troubleshoot then fix ignition, then you can troubleshoot and fix the charging system. "Power and switching" functions concern me much more than resistance readings.

Post results.

[TriNortchopz]

The Dyna 2Ki says it has:

"Intelligent over current / short circuit protection.
Every time power to the ignition is switched on, the 2Ki will check to see if the coil is shorted, mis-wired, or the wrong type.
If an error is detected, the 2Ki will imediately switch off and issue a warning by rapidly flashing the status indicator.
Besides protecting the unit, this also prevents the costly failure of an improperly matched coil going bad one hour into your ride.
After starting, the 2Ki countinuously monitors the coil and wiring status.
Intelligent overvoltage/overcurrent protection.
Ruggedized output - cannot be damaged by broken or disconnected spark plug wires."
http://www.dynaonline.com/products/h.../dyna-2ki.aspx


got a 'warning by rapidly flashing status indicator.'?

[69Glide]

I have a couple of questions..

Are you running single fire or dual fire?

When you time the 2Ki does the red LED indicator act as expected and described in the 2Ki instructions?

When you crank the motor does the red LED indicator flash on and off as the ignition cup rotates?

Do the switches on the 2Ki match your wiring? i.e. is the single fire/dual fire selection correct for the way your system is wired? If the ignition mode and the wiring is mismatched the 2Ki will time OK but you won't get a spark when cranking the engine.

In my experience the 2Ki is a very rugged and reliable ignition, they are tough to kill. Not saying you don't have a faulty ignition but you need to check these other things first.

Also, coils are not particularly voltage or current sensitive. The low voltage side of a coil is basically a long piece of wire with a certain resistance. Usually 5 ohms for points and 3 ohms for electronic. The current through the low voltage side is a function of the resistance - a low voltage circuit with a 5 ohm coil in a 12v system with out a ballast resistor will have a current of 2.4 amps when the points are closed. A 3 ohm coil will flow 4 amps under the same conditions.

Since a coil is designed to have one side of the low voltage circuit connect to battery (12V) and the other side connected to ground they are pretty hard to damage by overvoltage unless your regulator is really bad - and I'd expect to see damaged bulbs and other voltage sensitive components damaged as well..

The reason we use a 5 ohm coil with points is to maintain current at a level that won't quickly destroy the points. Since the average current in this circuit is defined by the dwell angel (i.e. the number of degrees the points are closed in a complete rotation of the cam) or duty cycle we need to protect the points by limiting the current.

We can use a 3 ohm coil with the 2Ki since we control the dwell angle (duty cycle) electronically.

Since the spark voltage level is directly related to the current through the low voltage side of the coil we see that a 3 ohm coil provides much hotter spark than a 5 ohm coil. That is one of the really good things about the 2Ki versus points.

This also explains why points don't last long when we use a 3 ohm coil with a points ignition.

A 5 ohm coil will not damage a 2Ki - you just flow less current and get a weaker spark..

Good luck with it.

69

[HaggardnShoved]

Hey everybody sorry it took so long with an update and a reply. My secondary resistance was 17.5k, so the coil was fluked. On top of that I was getting some serious arc off the ignition module, on top of that, the timing for TDC wouldn’t advance or retard enough within the modules limits to even turn the red light on, I was totally upside down. (I checked to make sure I was on TDC on the Front Cylinders Cycle).

Also moving the wires around the light would flicker on and off. It was an old used 2Ki that’s been around for a while in our shop. Just for safety I’m going to try another ignition module and coil and see how it starts up.

Only reason to try it is that another bike in the shop is having the same issue. Switched everything out with these parts and it’s running just fine. I’ll post results when it gets done this week.