Coil wire problems

[Reedcutter]

Hi everyone
Im hoping someone can help. I have a 1977 gl1000 with a dyna s ignition and 3ohm dyna coils. Shes been running beautifully since i fitted it all a couple of years ago. But she has been dropping out and missfiring on cylinders 1 & 2. I decided to try static timing. But when i conected my test light to the yellow wire fron dyna s . It lit up. I turned engine over by hand and noticed the light was constantly on. I unplugged dyna s to find i have constant live from coil. The other side coil worked corectly. I have tried changing the yellow and blue wires over but still a constant live on yellow wire. I have checked both coils and they are both reading 3ohms. Please can anyone out there help me! Thanks in advance

[ekvh]

Probably the module is bad. Dyna will test then for free and if bad usually offer new at about half of retail. The downside, it takes time.

Try pushing on the module. I had one where the solder joints were letting go. I glued a pice of rubber to the points cover so it would put pressure on it. It worked and I rode it until freeze up. Then I sent it in.

[Reedcutter]

Thanks ekvh
But the dyna s is putting the right pulses out. Its just im getting a constant live down the yellow wire from coil even with dyna s disconnected .

[Maz]

Thanks ekvh
But the dyna s is putting the right pulses out. Its just im getting a constant live down the yellow wire from coil even with dyna s disconnected .

The coils are constantly live via the black or black/white wire. The yellow and blue wires are usually grounded by the points (or Dyna S, in your case) so you should always have volts on the yellow and blue wires from the coils if they are disconnected from the points or Dyna S, if the ignition is on.
Maz

[Reedcutter]

Thank you Maz. So if i disconnect the blue wire to coil from dyna s . Should that then be constant live also then?
And as the dyna s has a live feed to it. Should i then get a pulse from the two dyna s wires that are disconnected? Got a bit of smoke coming out me ears with this on lol.

[Maz]

Thank you Maz. So if i disconnect the blue wire to coil from dyna s . Should that then be constant live also then?
And as the dyna s has a live feed to it. Should i then get a pulse from the two dyna s wires that are disconnected? Got a bit of smoke coming out me ears with this on lol.

Both the blue and yellow wires coming from coils should be live and read almost battery volts (it will be slightly lower due to the 3 ohm resistance of the coil). As the Dyna S performs the same task as points (it grounds the blue and yellow wires to charge the coil then disconnects to create the spark) you should be able to see the 'on/off' pulses as the motor runs. Try connecting an led test light from 12v to yellow and then from 12v to blue, while the motor is running or being spun on the starter (ignition on). In each test it should flash. I don't have Dyna S but I believe they have LEDS on the control box that do this very thing. Someone with Dyna S will confirm.
Maz

[Reedcutter]

Thanks again Maz. My dyna s dosent have a box with leds. It has the two modules that are on back plate. A live feed to both modules that clips to the turn signal constant live at relay. Then 2 more wires go to yellow and blue wires that go to coils. I bought this new a couple of years ago. That and the rotor was all that was in the box. Il get back out in shed this afternoon and have another look at it. I have a test light. Il try the 12v through it to leads of dyna s then Thanks again for your help.

[Maz]

Happy to help.
I was picturing a different system in my head (Newtronic) which has a control box with led's. Dyna S doesn't have this, as you point out. Operation is still the same though - it grounds the coils to charge them then disconnects to allow spark as coil discharges.
Good luck.
Maz

[Reedcutter]

Thanks Maz
I will post my findings later then thanks.

[Reedcutter]

Right feel we getting somewhere now. Ran test light from live on battery. Touched on each of the dyna s leads. One flashes when turning over. The other dead.
The blue/yellow wire from one of coils has power at coil end but not at dyna end. Could it be a corroded wire has caused the module to pack up? I think i can send unit to dyna for repair. I will look in to this tonight . Then il renew the coil down to dyna wiring.
Thanks again maz for your help. I was losing plot a wee bit then .