Dyna Coils

[terryt]

With all the talk about coils and leads. my dyna coils are playing up there are only firing on one lead. the top lead outlet on each coil is not firing so its only firing on 1 and 4 has any one else had this problem

[Fred Camper]

That just does not sound like a coil problem. On a waste spark system, two plugs fire at once and of course only one spark is worthwhile. Do you have points or an electronic ignition? I might suggest a problem at the timing plate down at the left cam as there is two pick up points under the timing cover and maybe one of those has come loose. Either points or an electric pickup needs both signals as I understand it.

If you are using points, maybe the capacitor is bad?

[terryt]

That just does not sound like a coil problem. On a waste spark system, two plugs fire at once and of course only one spark is worthwhile. Do you have points or an electronic ignition? I might suggest a problem at the timing plate down at the left cam as there is two pick up points under the timing cover and maybe one of those has come loose. Either points or an electric pickup needs both signals as I understand it.

If you are using points, maybe the capacitor is bad?

coilwiring.jpg

Thank Fred, that's what I cant work out two cylinders down one from each coil. I am going to take them off and check and test of the bike just connect the wires and have the coil were I can see it, if there's a spark say at 1 and 3 then 2 and 4 must also have a spark

[Old Fogey]

On either of the coils, due to the way the current runs if you have a current on one plug lead output socket and a spark, you must have continuity at the other socket. The current feeds out from one, through the lead and spark plug, through the engine casing, into the other spark plug and lead and back to the coil, meaning that both fire at the same time.
But you may have very high resistance in the system. You need to check the leads, plugs and plug caps.
Have a look here at a problem I found.
http://www.wingovations.com/#/plug-cap- ... 4543524764

[terryt]

New leads and plug cap fitted and tested before fitting to coils, same problem only firing on one terminal from each coil,
I took the coils off the frame and refitted them so I could see the connections tested the coils for ohms so wired them up left the plug leads off and checked for a spark only sparking on one terminal on each coil looks weak so getting a condenser going to try that, may try putting the dyn s back on to test but had issues with that trying to set static timing up had to file some off to get it better

[Old Fogey]

That is too weird. I doubt a new condenser will do anything.
Well, to get a spark at either plug the circuit must be complete. Current will take the path of least resistance, so I'm thinking that you have damaged coils, in that the current is somehow managing to return without having to jump the high resistance gap in the other spark plug.
Have you tried running it in the dark to see if there is any signs of shorts?

It sounds to me that you need to return the coils to Dyna for checking. I did that with a pair of mine which I though were bad; turns out they weren't, the Dyna electronic unit itself was gone.