DYNA green coil anomaly

[Al]

Can anyone say for certain whether it is possible for one tower of the two outputs (HT connections) not to work if the other one is doing fine?

I thought they were connected internally and had to; both or neither work for that reason.

Had a proper mare at Snetterton and with wet plug and a confirmed spark i could not get Number 1 to fire.
It started as a missfire initially and eventually packed up.

Three different plugs (two new from different sources), new fuses, swapped HT leads, stripped carbs, drained fuel, drained tank, checked all connectors, swapped dyna 2000 modules.

It was only really missing at lower revs to begin with and off load revving when static it would appear fine.
Eventually it would not even run on all four when static on low revs and under load number one failed to even missfire!

Battery at 14. 7 volts when running 12.8 when turned off.

20 people told me exactly what was wrong but their best and mine could not find the problem.

Any thoughts before i take it apart again.


AL

[mike_p]

Have you tried swapping the coils over to see if the problem moves with the coil ?

[Taffus]

I 've got some new grey coils to try if they match up with your 2K

[Garn 1]

I hope I have your terminology correct....
By "towers" you are referring to the two "spouts" on each of the green coils.
Using a multi-meter set to read resistance, you should get a reading of approx 14k ohms, by setting the probes to the contacts at the bottom of these towers. Should be the same on both coils. This is a check for the secondary windings.
To check the primary windings measure resistance across the two screw terminals on the coil body.. should be about 3 Ohms

Note the primary terminals are very close to the mount and sometimes some electrical shrink tube is put around the mount to insure insulation!

RegardZ.

[Al]

Thanks.
Mike p; not coils but swapped known lead for the one on the dead cylinder lead and no change. Still no fire on Number 1

Taffus; thanks i may do just that if the coils from Brian 1100R aren't available

Garn 1; yes that a bit ambiguous. I meant spouts or HT outputs. The J setup uses the two outer pre-drilled holes in the iron core so not a problem with shorting like it is for the earlier bikes.
These are also my own coil brackets so clearance d and drilled for air circulation.
Will do the full suite of coil tests as per DYNA instructions as i have readings from when i fitted them new,... about three or so years ago.

Maybe the penny drops albeit softly just now.
I run the two inner cylinders richer and the two outer ones leaner. Currently the two inners are set to be run very rich. I didnt make a connection at the time but thought it odd when i took the four plugs out; the two inner were correct mixture and the two outer were a tiny little bit darker but no where near enough to suggest a missfire or poor running.
Thinking about it and the fact that they should have shown up weaker than the middle two i am leaning toward a failure of the coil.
Partial on number four or pending and actual on number one.

Have no time just now so will do some serious testing around the weekend and beyond.

Thanks again.

AL

[RALPHARAMA]

These coils are known a 'double ended' as are 99.9% of coils use on fours. I have never come across a coil that was fine one end but not the other, but I guess anything is possible. I have to say I have never been impressed with the reliability of Dyna coils. Duff leads, however are commonplace as a stroppy plugs!

Many are not mounted properly which doesn't help with longevity.

[Al]

Earlier on yesterday:
I had dry steamed one green coil to simulate overheating and frozen it in the freezer for the opposite.
Results HT;
Room temperature 18 degrees C....... 12.7k ohms
Very hot /damp....... 15.4K
Fridge at 4deg C........ 12.7K
Freezer for 2 hours..... 11.5k
Freezer for 4 hours..... 11.4k
Should be between 13.5K and 14.5 K
Dynatec say that anything over 10K should be fine.

LT;
3.5 to 3.6 ohms consistently with meter leads measuring .07 ohms giving 2.9 ohms for the faulty coil after subtracting the resistance in the leads.

Technically and for practical purposes i am loathed to condemn this coil because it appears to be only just outside the perfect operating parameters.
Dyna say that damaged coils will have very different reading from those stated as 'normal' which these are not.
I will need to do some substitution and so forth.
These were new when i fitted them in 2010.

Today:
Swapped leads on the 1 and 4 coil and the missfire (non running cylinder) moved to number 4 and number 1 ran fine.
Swapped the pair of coils for borrowed grey ones (thank you Brian 1100R) and it fired up on all four instantly!!
Bastard!!!!!!!!!!!!!!!!!.
This means that only one of the two output HT towers (spouts) is functioning on the 1 and 4 coil.
Dont know how that is possible as i thought they were connected together as a pair!!!!

The continuity / resistance test that i did (which is not one of the recommended tests) shows that it must be internally shorting (albeit fractionally when tested off the bike) on one of the outputs because all the other parameters are just about within the sphere of acceptable spec!
That was to test between HT and LT circuits of the coil at the highest scale my meter will read for ohms.
At 200M ohms it just showed a tiny resistance which the other three did not.
That i am assuming means that there is a co-responding continuity if you can detect a resistance value on this coil only.
However once it has voltage applied to it i guess it becomes more of an issue!!!!
Very lucky for me that it was still miss-firing when i put my coil back on or i would have had nothing to compare with.
Some you win and some you don't.
All the voltage and resistance checks that i did prior to running it up showed that there was no (less than half a volt) drop between the battery output and the coil wires.
No other issues were detected anywhere including the quality of the fuel and the associated peripherals to the ignition circuit (such as it is now).

So there it is, that is the answer to the question and you can have one spout not working if the other is apparently fine.

Will see if Dynatec will play ball tomorrow but if not will be after a set of mint new coils if there are any about.

AL

[garyd]

Al.
I've got a brand new set I won't be using if Dynatec come up short.

[Al]

Thanks Gary i am going to try talking to them nicely tomorrow Monday.
That will be a first for me

AL