1000 SFC ignition/new coils

[Laverdalothar]

I know many have used the TEC coils with success in the past, but I was thinking that replacing 37 years old coils with 25 years old ones might not be a wise decission. I made some reserch and found the Dyna coils on the Sachse webpage. Dyna coils have connectors for connecting the ignition lead and as they were roughly the same size as the original ones, I thought I'll give it a try... I ordered 3 single coils, new NGK plug caps plus 2 meters of ignition leads. I also bought me a new crimping tool, specially made for ignition lead connectors to make sure the connectors get perfectly connected to the leads.

Of you go:


The new coils were a bit wider than the old ones, so I could not mount them the same way as the old ones and had to re-position them. I found a nice solution which fits perfectly into the triangle of the frame without drilling one singel hole into the original bracket:



I was unsure if this would really fit into the triangle as space is really tight there, especially with the brackets welded on for stiffening the headstock. But - after a while I found out how it works and mounting it was a question of minutes:



Put 3 fresh spark plugs into the ignition caps, layed them on the cylinder head to ground them, turned the key and pressed the starter - 3 sparks in good quality that I have never seen before on the 1000 SFC!

put the ignition caps back onto the spark plugs and the tank back on, connected the fuel lines and primed the carbs, pulled choke a bit, turned the key and pushed the starter button and - did not start... after a while, it started "farting" (pofff....pofff...) and tried again and again and after some seconds, it barked into life but ran a bit rough. I gave it some time to burn the old fuel and get fresh one and then, it ran better than ever in idle, picked revs quite nicely and was realy running smoothly!

So - good 2nd day of the year! Now it needs a testrun to see if this was the solution to my innitial issues. I hope it was...

 

[renetriple]

Good job !!

 

[iis_iis]

Amazing, motoplat red ignition coils, Spanish for problematic coil, still in use on your machine, many was the long day trying to sort out ignition problems on a Corsa. There are two types of outwardly similar motoplat red coils, in electrical termination internal. One type is much worse than the other. Been covered many years ago, maybe on this forum the background is to be found. Used TEK coils mainly for the availability and known reliability, not too mention the $0 to 5 to 10 or so they cost, grin.

Dependent on type of actual ignition in use, you will need inline 5K Ohm resistor caps or inductive suppressing SS HT leads, not 7m/m lawnmower HT lead or car carbon core silicon HT. Erratic cold crank and running is a notable for incorrect HT lead assemblies.

Not knowing your original problem, getting rid of the red motoplats is a sound move 100%. j.

 

[Laverdalothar]

I have the DMC 2 (I think) installed with the optical sensor. The original coils were 3K Ohm, the original caps were also 5K Ohm I think. I will check again, but I think the new ones are 5K Ohm, too. I use spark plugs without resistors. No erratic running of the bike recognized, but thanks for the heads-up ;-)

 

[bobsotto]

I know many have used the TEC coils with success in the past, but I was thinking that replacing 37 years old coils with 25 years old ones might not be a wise decission. I made some reserch and found the Dyna coils on the Sachse webpage. Dyna coils have connectors for connecting the ignition lead and as they were roughly the same size as the original ones, I thought I'll give it a try... I ordered 3 single coils, new NGK plug caps plus 2 meters of ignition leads. I also bought me a new crimping tool, specially made for ignition lead connectors to make sure the connectors get perfectly connected to the leads.

Of you go:
View attachment 60983

The new coils were a bit wider than the old ones, so I could not mount them the same way as the old ones and had to re-position them. I found a nice solution which fits perfectly into the triangle of the frame without drilling one singel hole into the original bracket:

View attachment 60984View attachment 60985

I was unsure if this would really fit into the triangle as space is really tight there, especially with the brackets welded on for stiffening the headstock. But - after a while I found out how it works and mounting it was a question of minutes:

View attachment 60986View attachment 60987

Put 3 fresh spark plugs into the ignition caps, layed them on the cylinder head to ground them, turned the key and pressed the starter - 3 sparks in good quality that I have never seen before on the 1000 SFC!

put the ignition caps back onto the spark plugs and the tank back on, connected the fuel lines and primed the carbs, pulled choke a bit, turned the key and pushed the starter button and - did not start... after a while, it started "farting" (pofff....pofff...) and tried again and again and after some seconds, it barked into life but ran a bit rough. I gave it some time to burn the old fuel and get fresh one and then, it ran better than ever in idle, picked revs quite nicely and was realy running smoothly!

So - good 2nd day of the year! Now it needs a testrun to see if this was the solution to my innitial issues. I hope it was...

Hi Lothar,

I did it a little different with same Dyna coil for my RGS. Not a good picture but the coils are turned 90 degree compared to yours and mounted on small angles in the same plane. Had to drill new mounting holes in the original mounting plate.
/Arne

 

[iis_iis]

NGK covers ( why "covers"? ), the 115 degree type with internal 5Kohm resistance were fit for purpose, though do fail in time, internal fracture of the resistive element. Low cost and quickly replaced, allows use of standard spark plugs. The resistance slows rate of secondary HT current to mitigate cross firing of adjacent leads and coils. Not a big problem with points systems, though when electronics is applied, things change. Old style "CDI" systems can indeed cross inductively couple HT systems with chronic cross firing and misfiring.

Noticed Lothar you had 90 degree rubber spark plug caps, and possibly inductive suppressed HT lead, even better than NGK/7mm HT lead. On the iis systems, where possible i used magnecor 8m/m lead and SS terminations each end. Though the NGK/7mm was more available and no special tools required to fabricate.

Mention the "5K" aspect for HT leads as when i did a customer install many years ago, the motor started then all sorts of erratic running when we attempted further cold crank starts. Owner was present and thought the iis not working, he had used non resistive NGK cap/covers, not obvious from inspection, knew what was the problem, and closely inspected the covers, replaced the covers, motor ran as designed. Main point of my post for others with perplexing misfiring or similar. Easy things first.

Nice neat work for Arne as well, though as you know, RGS 120 motors drown the coils in the rain,waterproof connections require extra attention. j.

 

[bobsotto]

NGK covers ( why "covers"? ), the 115 degree type with internal 5Kohm resistance were fit for purpose, though do fail in time, internal fracture of the resistive element. Low cost and quickly replaced, allows use of standard spark plugs. The resistance slows rate of secondary HT current to mitigate cross firing of adjacent leads and coils. Not a big problem with points systems, though when electronics is applied, things change. Old style "CDI" systems can indeed cross inductively couple HT systems with chronic cross firing and misfiring.

Noticed Lothar you had 90 degree rubber spark plug caps, and possibly inductive suppressed HT lead, even better than NGK/7mm HT lead. On the iis systems, where possible i used magnecor 8m/m lead and SS terminations each end. Though the NGK/7mm was more available and no special tools required to fabricate.

Mention the "5K" aspect for HT leads as when i did a customer install many years ago, the motor started then all sorts of erratic running when we attempted further cold crank starts. Owner was present and thought the iis not working, he had used non resistive NGK cap/covers, not obvious from inspection, knew what was the problem, and closely inspected the covers, replaced the covers, motor ran as designed. Main point of my post for others with perplexing misfiring or similar. Easy things first.

Nice neat work for Arne as well, though as you know, RGS 120 motors drown the coils in the rain,waterproof connections require extra attention. j.

Other side of my installation with Superseal connector
/Arne

 

[Laverdalothar]

Hi Bob, nice way, too. I wanted to avoid any additional drilling and thought that the way I mounted them, they might even get a bit more cooling (not that I would say it would make any difference, just for peace of mind ). Thanks for sharing, though!