dyna ignition and coils

[DrewArit]

Turns out my coils are bad on my 74 cb750k4. I am looking to replace the stock system with a dyna electronic ignition.

I am looking at the ds1-2 ignition, but am not sure what coils to pair it with. any suggestions??

[DrewArit]

oh, and what are you guys' takes on iridium plugs???

[woodsrider250-2]

http://www.z1enterprises.com/catalog.aspx?pid=CB750K4-1974-IG0

My $ would be on the grey ones for best performance (closest in resistance to the Dyna).  The other 3ohm ones will work too.  Call Z1.

The fine-wire plugs are great w/ a CDI ignition, and hotter coils!

[Tech78]

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[Re-run]

The best thing to do if you have a completely stock system is to get the dyna 5 ohm coils. The 3 ohm coils are known to drain the earlier systems till the battery died. SO the dyna with 5 ohms is the best way to go. Now if you change to leds, then the 3 ohm would be fine.

[sgtslag]

My 1979 K was slow to start up, requiring the starter to grind for 5-10 seconds, 1-2 times, before she would start -- and that was after I had turned the gas on for 5-10 minutes before trying to start it!  I figured the 30-year old coils were weak, but I did not want to invest in new coils, if I didn't have to.

I read up on the Iridium plugs:  supposedly lower resistance for the spark, requiring less energy to jump the gap; $8/plug ($32 total), instead of $150-$200 for two, new, dual coils.  I bought a set of NGK Iridium plugs, and put them in.  When I hit the starter button for the first time, I jumped out of my skin -- the engine was running the instant the switch contacts closed!  The old plugs were original, but they looked good, and the bike ran smoothly once it started.  With the new, Iridium plugs in, it runs even smoother, and it starts instantly, even 10,000 miles later.  Aside from needing less energy to jump the gap, they will last longer, as well.  In a car, Iridium plugs are good for 100,000 miles; in a bike, they should be good for 30,000-50,000 miles.  Time will tell.  I switched my 1993 Voyager to Iridium plugs also, but I did not see as big of an improvement in that bike -- don't know what type of plugs I pulled out of it, but it has newer, stronger, coils in it, and it is more advanced than the 1979's ignition system.  Cheers!