Topic: On my 3rd dyna s in less than a year...what gives?

[750four]

So my 71 cb750 is killing my dyna s system some how. Electricaly I've put in the dyna s and dyna 3 ohm coils, cyclex charging system on this last unit that died. Dyna s is behind a 10 amp fuse.

So last week after putting a new charging system in I was pleased to be able to take a spin on the cb, maade it out for about a 15 minute ride and then parked it for a bit. Went to head home and fired it up in the parking lot fine, didn't make it 50 ft down the road before cyld 1 and 4 died.

After I got it home, I checked for spark with no luck. Started digging deaper to find my ignition module on the 1 4 is not turning on and off. It's at 9.5 v no matter where the rotor is?

I'm going to try to rewire a few things and replace my crappy autozone key switch. Just in fear that it is leaking voltage into the ignition even when the bike is off. Also going to pull power for the dyna from the tail light. It tied into the coils power as of now. Uhhh...

Anyone ever had a similar problem? Any other ideas?

Also the bike had another problem with the exhaust valve guide possibly leaking oil onto the plug( or so I suspect) the head I have did not have valve guide seals on the exhaust valves. My 1 cyld has been discolored a golden hue. I've been rocking it side to side before I fire it up.seems to fix it. Maybe fouled that plug, can that stop the coil from expelling spark and revert back to the dyna s?

[lucky]

WOW!! 3rd Dyna ignition in a year!
Did you have to pay for all 3 of them?

When you get the Dyna ignition it has requirements for the coils that you are to use.
You did not tell us WHICH DYNA ignition that you are using.

Also the stator, coil, and rotor have to be good.

One thing that can ruin a coil is leaving the ignition switch on without running the engine. Make sure that when you turn the key off that the coils are not getting 12 volts. See if they get hot when the key is in the off position.

[Greggo]

You did not tell us WHICH DYNA ignition that you are using.

It's in the title.  Dyna S.

[TwoTired]

Does it have resistor plugs?
Does it have resistor plug caps?
Does it have resistance wire to the plugs?

What voltage does the charging system drive the battery up to in a long haul?

[750four]

Plugs are dr8eix ngk iridiums. Wires and caps are dyna solid copper cores. Not exactly sure what it's charging up to. Just put the Cyclex charging system in. Using a small sealed battery, but I do know it was charging and after the short ride and stop I checked the battery and it sat at 12.9 v. Which is a full charge for that battery. I bought a new key switch and will check the other to make sure the v is not getting into the ign somehow.

Do you guys run resisters, relays, or anything else between the dyna s?
I have a sparx capacitor I might try instead of the battery also. This charging system is supposed to be able to run batteryless too.

Also to answer your question: I killed the first, sent it back to dyna. They said nothing was wrong with it?, it was fried... Bought a new unit at a discount replacement from them for 75. They also checked the coils. Seemed fine too. Recieved the new dyna s unit and coils back. Installed them and began the fight with the charging system.

Replaced the whole system with the Cyclex 2 phase kit. Works great. First test ride and my 750 is running on 2 cylinders after 20 minutes. Pulled the ign and coils back off and the are back on there way to Dyna. Hopefully they will just replace the ignition.

I really can't see how there is anything different that I've done. Shouldn't be having these problems really. 

Anyone have there dyna s wired up with no problems?

[Stev-o]

My K4 that I bought 6 months ago has a Dyna system, no issues.

Something is def wrong. Do you have stock points/coils/plugs that you can put back on to test?

[TwoTired]

The dyna isn't failing while the bike is resting with a 12.9 V battery voltage, is it?

However, if the tiny battery is being charged over 15V to say, like 20V, that would stress the dyna. (Which is why I asked for a battery voltage after a long run.)
Also, in stock bikes, the large battery capacitance damps ripple voltage and noise spikes throughout the entire electrical system.  A Points type ignition system wouldn't care about these noise spikes.  However, transistors can get quite stressed when zapped with voltage excursions beyond their tolerance.

Does the Dyna documentation give an operating voltage never exceed value?

So, you have an ignition, battery, and charging system that is NOT stock and was never engineered to work together before your assemblage.  If you want to get to the root, you may have to do some engineering, which begins with gathering data. imo

Cheers,

[lucky]

You did not tell us WHICH DYNA ignition that you are using.

It's in the title.  Dyna S.

Thanks Greggo.

I thought there were numerical designations like Dyna S 2000 and so forth.
I am interested in your problems too because I have the Dyna S ignition .

[Greggo]

You did not tell us WHICH DYNA ignition that you are using.

It's in the title.  Dyna S.

Thanks Greggo.

I thought there were numerical designations like Dyna S 2000 and so forth.
I am interested in your problems too because I have the Dyna S ignition .

Yes.
The Dyna S is different from the Dyna 2000.  The 2000 lets you customize the ignition timing, and advance curve.

[750four]

The ignition is not " failing" , it has failed. Dead, not working, sleeps with the fishy's'...lol
The dyna s is engineered to work on the cb750, aswell as the cyclex charging system. 1 and 4 on the ignition is no longer sending a signal, it doesn't turn on or off. That lead reads a constant 9 ish v's if the rotor points to it or not.

Just tring to figure out what is causing the problem here. It would be hard to believe that I 'm the first person to use this combo. I havent really had a chance to take it for a long haul, but the short ride I did started at 12.7 and15 mniutes later it sat at 12.9. Doesn't seem like it is frying.

[TwoTired]

Good luck then...