Ignition tales ...

1200 JOTA

1200 JOTA

Senior member
Location
Australia
Because I'm just a tinkerer and not an expert I thought I'd relate some of the results of tackling a 'miss' I've had for a while on the 1200.

Basically relating to the Ignitech box ... there has been some missing at higher revs. ( > 4000 rpm) and I'd set the ignition as recommended by those in the know to Auto (sensing the coil resistance and dwell etc.) with a dwell addition of ~ 25% and was using dynamic dwell addition of ~ 20%.
The coils are Dynatek minis @ 3 ohms (one dual fire) (which are said to be pretty useless) (might agree) but I've finally found an answer of sorts.

Thinking that I wasn't getting enough dwell (charge time) I was upping the dwell, finally 125% to 150% and it ran like sh*t so came home again and reset the box to only a 10% addition. Voila! It actually ran great.

So, for those with an Ignitech ... AUTO might work well for you.
 
I've stopped using Dynatek Mini Series 3 ohm coils for that exact reason, misfire through the 4,000 rpm range
You can play with the dwell settings and get the engine running clean but next bike with same set up and using the same settings does not work and have to trial and error all over again
 
If using Auto in the dwell settings and its on a triple with single coil and twin coil. you have to put the twin coil on channel 1. As the Ignitech box in auto only measures the current flow to set dwell on channel 1. As the single coil will saturate faster and if it is on channel 1 the twin coil will not reach full saturation and give you poor spark. This one of the reasons you can get a better result with fixed settings
 
That's interesting Jugs. I've actually got two twin coils on my Jota. One of them has the second plug lead connected to the bike's earth, or ground or battery negative as John W prefers. The dwell is set on Auto. I don't remember which is coil 1 as far as the Ignitech is concerned, but in my case I guess it doesn't matter.
 
Anybody using 3, twin-output coils on dual-plugged heads? How does the Ignitech work with those?

Curious from Sydney
 
yes its been done. With a John Wilson Ign then a Ignitech. Creating a curve for the Ignitech was the biggest problem as we did not have access to the curve in the John Willison Ign which was a special just for the 6 plug head. ended up with way less advance as you would expect.
The Ignitech dose not know if its a twine coil or not so wiring is same. you do have to set dwell up for twin plug coils though.
 
Dellortoman said:
That's interesting Jugs. I've actually got two twin coils on my Jota. One of them has the second plug lead connected to the bike's earth, or ground or battery negative as John W prefers. The dwell is set on Auto. I don't remember which is coil 1 as far as the Ignitech is concerned, but in my case I guess it doesn't matter.
Click to expand...
Good man Cam, there is no "Earth" we are all floating..... am so witty... wince. As you decided upon, two coils of same twin tower or output form, ground the unused...oppps there it goes again..."ground"... output on the single center cylinder, means you can trouble shoot swapping coils as may be required. Did that on all the European IIS sent, ie included TEK coil banks with the kit...j
 
Jugs_S said:
yes its been done. With a John Wilson Ign then a Ignitech. Creating a curve for the Ignitech was the biggest problem as we did not have access to the curve in the John Willison Ign which was a special just for the 6 plug head. ended up with way less advance as you would expect.
The Ignitech dose not know if its a twine coil or not so wiring is same. you do have to set dwell up for twin plug coils though.
Click to expand...
That twin plug head ( ex one of my doner heads in the day BTW ), was indeed a significantly reduced overall maximum advance, around 25DBTDC as i recall with confidence, initial off idle advance was less aggressive as usual non CR head engines. BTW not that hard to map ignition box curves, did a few on the DMC's i had to hand, when i noticed the published curves for the DMC were not what was actually included in the DMC module. Use a quality dial back timing light and with a helper, plot the advance up to 4Krpm, nothing to be gained above 4krpm in fiddling with advance, others may have different experiences. HTH j.
 
FWIW, "3 ohm coil" has little relevance when your seeking to achieve the best "dwell", what really is in play, NI or ampere turns, inductive reactance a term that needs to be included. The higher the inductance of the primary winding the more dwell required for ideal saturation ( there is a peak value ), becomes complex though simplified it can be better understood when your fiddling with a system that varies dwell.

Would imagine a situation of current limited ( CC ) coil drive, working against an ideal dwell performance, unless the actual coil characteristics are known and applied inside the ignition control module. j.
 
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