Dyna S troubles, thoughts?

I've been reading a lot on other forums lately about people having trouble with their Dyna S ignitions, and just this week had mine on my 78 GL1000 fail. I know a lot of people have great luck with their Dynas, and know that they aren't crap, so I got to thinking. Of those instances where the Dyna failed, what type of coils were being used? On my GL (the only Dyna I have experience with and it was installed years before I ever got the bike) the stock coils were still in use. Could the ohm rating of the coils not matching up right to the Dyna contribute to failure? I'm pretty much an infant in my understanding of electrical systems, so this thought may be way off base. Just thought I'd throw that idea out there and see what other people's experience/thoughts were on the idea.

Just to be safe when I ordered my new Dyna today from Jeff at Z1 I got the green Dyna 3 ohm coils that are matched to the Dyna S. Figured it couldn't hurt to replace 30 year old parts anyway.

BTW, if you're reading this, thanks Jeff!!

You're lucky the coils lasted as long as they have. It's a harsh environment the ignition coils live in, under the gas tank on most bikes, little to none air cooling except when moving, trying to ignite low octane fuel at the sparkplugs under compression, working with lower voltages than originally designed due to corroded wiring and switches as the bike ages.

True that!!! The coils weren't my issue though, it was the Dyna S. Intermittently it would start cutting out, the bike wouldn't die but it would lose all power. After a lot of headache and investigation I traced the problem to the Dyna S, only because it started acting up on the first start up in the garage instead of it's usual failure while out riding down the road...
But anyway, just wanted to check with other people's experience with Dyna failure and see if there's any correlation to the type of coils being used.

I agree, its a rough place. And suddenly you've started to send more power through them than they're used to.

Going with those green coils is a good idea, thats what I've got on the 650 with my Dyna. I'd do the WG coil wiring mod while I was at it too. Might take a bit more effort since its on a GL and it wont be 100% the same, but I'm sure it's do-able.

I'll for sure be checking the voltage at the coils while I'm in there. The coils on the GL are a PITA to get to. I'm going to have to remove the airbox and the shelter frame in order to get in there (and maybe even drop the radiator), so I only want to do it once!!! Shouldn't be too much of a difference in wiring the coil mod though, systems are basically the same so I'll just have to follow the schematic. I've got the coil mod done on my kz650 and it made a world of difference.

I'll just relay my experience with Dyna and coils.
1978 KZ650 167,000 on motorcycle, 157,000 on Dyna III ignition, one failure covered under warranty. Orignal coils still in use working fine. I tried the Dyna coils and found no advantage to them so stayed stock.
1977 KZ650 65,000 on motorcycle, 40,000 on Dyna S. No problems. Original coils still working fine.
1979 KZ1000MKII 80,000 miles, original Kawasaki ignition. Original coils working fine.
So I'd say I've had exceptionally good luck with coils and Dyna.

Most of the Dyna-S failures are triggered by charging system woes.

A bad regulator will allow very high voltage to spike the Dyna-S. 17v-18v or more is not unusual when a regulator fails.

Low voltage is another cause of failure. Poor wiring (including ignition switches, kill switches and all the connector blocks and bullet connectors), weak/dead batteries can cause problems.

It's well worth checking your voltage at the battery, then again at the coils. A good, full charged battery should read a little over 12.5 volts. It's unusual for you to see much better than 11 volts at the coils - and in bad cases as little as 9 volts. While there's a simple wiring relay 'fix' to help power the coils - this doesn't help with the ignition, so it's something where cleaning all connectors can help.

Heat can also cause the Dyna-S some problems. With performance engines, esp. air cooled engines it's easy to get the ignitions to cook. That's tougher to do in the watercooled bikes.

in all the years i've been installing dyna ignitions about the only failures i have seen have been from getting to hot [leaving the ignition switch on ] or from ignition coils cracking and then shorting out on the frame tubes.

Dyna specifies 3 ohms as the minimum resistance for the coils. If lower resistance coils are used, you are exceeding the current limit on the Dyna S. Some have reported success with 2.5 ohm coils, but not sure if they were used for any length of time that way.

Leaving the ignition on with a Dyna S is definitley bad if the bike is not running. It usually has full current going to both coils during that time. That's a lot of heat to dissipate.

The factory electronic ignition does not do that, so is safer.

Ive seen one fail before on a friends bike but mine is 33 years old, 3/4 of that with stock coils and the rest with green Dyna coils & grey Dyna wires. Its an 1105 , SBM head & cams with 29 smoothbores and you literally just touch the starter button and its running

I have the 3.0 ohm(green) DYNA Ignition coils on a 1980 KZ750-E1 bike,for about 3 years,and the only trouble I had one time was I developed a high-speed miss,and couldn't find anything,so a buddy said: check your coils(I previously had a gas tank venting prob and a petcock[vacuum type]prob on this bike-so I checked those and everything was A#1). I removed the coils,and had my KAWA machanic bud do the 'dynamic' test on them(not the static[ohm] check-which is OK---better than nothing,but is not as accurate/does not check the coils "in use"). This test applies juice to them to see if they are firing-off the way they are supposed to. The results were: 1-4 firing good,but 2-3 firing,but as he put it: "the firing was diffuse/it wasn't firing it out there!" I sent them to DYNA and they tested them,and found out that the connection points on that coil needed cleaned up-they sent them back NO CHARGE! Good peeps to deal with. They even tossed me a pair of the HI-OUTPUT wires(Red)-for the shipping cost! can't beat that with a stick! BTW-I am not running a DYNA S ignition on this bike-never did. The pick-Up coil set-up(stock),never gave me trouble,so I never bothered.The bike runs fine!!!

Jeff.Saunders wrote:

A bad regulator will allow very high voltage to spike the Dyna-S. 17v-18v or more is not unusual when a regulator fails.

Hmmm, perhaps a 15V zener diode across the power lead to the Dyna S might offer good protection.