Potential Ignition Woes with a Dyna 2000 (long)

[SlowOldGuy]

I had a disturbing incident on Sunday.  I rode the '85 to work and on the way detoured to what passes for a few twisties in this area.  Probably less 80 miles.  At the end of the ride , I stopped by work (which was where I told my wife I was originally going) to pick up some data.  I was at work for about 30 minutes.  

Everything was going fine, bike started easily (as usual) and ran well (as usual of course).  Outside temperature was approaching 100 degrees toward the end.  Distance from work to home is approximately 18 miles, 15 of them are highway.  Light traffic moving along about 70 mph.

As I merged onto my exit, about 3 miles from home, I rolled off the throttle to slow down to the service road speed.  As I feathered back into the throttle, I noticed a vibration and less engine response than I anticipated for the amount of throttle I was giving it.  

I glanced down at the dash and immediately noticed that the tach was reading zero; however, the engine was still pulling although very labored.  I quickly realized that I probably only had 2 cylinders operating and started playing with the throttle to see if I had a chance of making it the few miles to home on the remaining cylinders, or if I needed to start looking for a safe place to pull over and get out of traffic.  

The engine would still accelerate and I managed to make it all the way home.  First thing I did at home was spray water on the exhaust headers.  Sure enough, 1&4 were extremely hot and 2&3 were only warm.  That explains why the tach was reading zero as I believe the tach signal originates from the 2/3 coil.  About an hour later, I started the engine up and all 4 cylinders were working.  I put a fan in front of the motor and ran it for about 15 minutes and everything was fine.  I wanted to take it out for test ride, but had family obligations that prevented any further diagnosis.  

The details:  I'm running a Dyna 2000 with Dyna grey coils and plug wires.  The system was installed about 5 years ago.  About a month after the original installation, I was out test riding and the whole ignition system shutdown and left me stranded on the side of the road.  That problem  wound up being a bad coil which Dyna replaced.  According to their explanation, the ignition system "sensed" the "bad coil" and shut down the entire ignition system.  This was a real pisser since I had coasted into the parking lot of a Honda dealer and spent several hours tearing in to the bike trying to solve the problem.  They were nice enough to send a service person out to see if he could help (he couldn't).  I finally towed it home and found the bad coil with my ohm meter.

Bear with me while I think out loud here:
This time, the ignition did not shut down as I still had fire on the other coil.  I believe power comes from the same wire for both coils.  Even though they have different connectors I should only have to chase the power wire back to where it splits off).  I'm thinking the coils are fine since the ignition box didn't shut down both coils this time.  Although I really don't see how the ignition box could "know" that a coils is bad even though the Dyna Rep told me it can.  

The ignition system is fairly simple, its job is to interrupt the ground leg of the coil at the correct moment to make the coil discharge and fire the plug.  The ignition box only interacts with the ground lead from the coil.

So, I'm thinking to concentrate on the following areas.

One is an open in the power wire or maybe a corroded connector.  Couldn't be a short as no fuses blew.

Next is a potential pickoff problem.  Shorted or open wire or intermittent connection.  If the ignition doesn't see the pickoff signal, it won't fire that coil.  But it could still fire the other coil.

Finally, bad circuit in the ignition box itself (of course this is the most expensive (most likely) problem).  Could have overheated and caused an open circuit, or component breakdown which went away after cooling off.  Maybe I'll take a heat gun and gently heat up the black box.

Looking for second opinions and different points of view on anything I might be overlooking.

Thanks
DavidR.

[Pat Conlon]

David, here's a couple of random disjointed thoughts:
1) Did you do a voltage and ohm reading at the power leads to each of your 2 coils.....if so, are they the same? or are they different #'s?
If the numbers are different (high ohm and/or lower voltage reading on coil 2/3) perhaps sidestep the whole issue and do the spst relay mod to get clean 12v power to your coils?
I recall the installation pictures of your Dyna grey coils, and the insulated plastic tubing you slipped over the frame to prevent arcing at the coil terminals...
2) Are you getting a intermittent ground fault on the power to coil 2/3? Any evidence of arcing?
3) Are the power/signal screw terminals on coil 2/3 ok? Could the coil terminals be damaged by the vibration of the terminals against the plastic tubing?
4) How is quality of the triggering signal to coil 2/3, is it the same as coil 1/4?

Cheers!  Pat

[rktmanfj]

Is the ignition box easily opened?

Is the circuit board potted?

I've never seen the inside of one of those, but if it's not potted you might start looking for cold solder joints.

Randy T
Indy 

[SlowOldGuy]

Pat,
I haven't had a chance to put an ohm or volt meter on anything yet.  There's no vibration in the coil mount.  However, I might just swap over to the super-sweet Jon Cain coil mounts that I got several years ago and never got around to installing.

No evidence of any arching when I was swapping the carb bank a few month ago.  Very few miles since then on this bike. 

I believe the Dyna box has an adjustment mode where you can rotate the crank and verify the pickup signal.  The box flashes an LED when it see the pickup signal.

My biggest problem is the symptom magically went away when the bike cooled off for a bit.  That sucks for diagnosing, I'd much rather have a hard fail.  Now I have no confidence for fear that I'll be stranded on the side of the road when it takes a dump again.   Not much fun in triple digit heat and full gear (even when it's mesh gear this time of year). 

I'll post any progress, but this could take several weeks.  What sucks even more is the YZF rear wheel is finally ready to install so I was looking forward to riding on modern rubber.  The Harley tire will remain on the old wheel and be mounted on the wall in honor of the exceptional service it has given me over the years.

DavidR.

[racerman_27410]

Dang i absolutely hate intermittant electrical problems..... I 'm with you in wishing for hard fail.... easy peasy to fix those.

i'm kind of leaning towards bad coil..... get hot and a small break in the windings opens up.

unfortunately there really isnt a way to bench test this... possibly vibration plays a part as well.

one thing is for sure.... the coil does all the hard work in the system and regularly gets cooked with heat up off the engine.


i dont think anything that could go wrong with the pickup assembly would self heal after the bike cooled down but like you said the dyna has a test feature...its magnetic...... i really dont think the box can detect coil failure and shit (oops) down the entire system.

like you said i think its just an adjustable ground trigger with minimal (if any ) logic.

i also dont think a cold solder joint in the ignitor box would self heal either

kinds of leads right back to a bad coil IMO.


i think i have one going bad since i have been having (almost) the same temp related problems but my tach still works.

no problems in colder weather but once the temps get hot (anything over 85F and extending highway running= good heat soak) it starts dropping two cylinders....cools down and everything is back to normal.

sounds like we're chasing the same gremlin.

want to split a new set of coils ? i'm running the greys too.

KOokaloo!

[RichBaker]

 Did you solder the connections or crimp?  Soldering is more prone to vibration failures..... Solder with shrink or tape may break, but not necessarily stay open, depends on how good the wrap keeps things in contact. Pull every suspect connection, if broken it will be obvious.

A cold solder joint can be very intermittent, especially with heat. As it heats, it will open, then close as it cools off. Eventually they can stay open, but not always.

[Flying Scotsman]

I think you should check the plug wires. Sounds like caps are lose and making contact when cold but not when hot.

[JMR]

 Several fella's I work with on projects have recently had very bad luck with Dyna 2000's and coils. A dragrace cb750 Automatic I built the engine for had both a bad module and 2 bad coils. Another CB750 engine build I did had a bad module and was replaced by Dyna under warranty. It took a while for Larry at Dyna to admit there was a problem BUT I think it was secondary to the intermittent nature of the problem. Another associate of mine in Georgia had a bad sensor plate, wrong rotor for the intended application ( it fit but added about 40 degrees of advance). I run several 2000's one of which is on my FJ. I did experience a problem several years ago with what appeared to be an over advanced condition. I would roll on the throttle and the engine would knock like 20 degrees of advance had been loaded in. This happened twice over several days. I sent the module to Dyna to test and they said it was good. The problem but has not occurred since then.
The 2/3 nature of your problem would make me think coil related or 2000 harness connected BUT that is a guess. As a side note I also believe the Dyna suppression wires aren't that great. I used to change them after several years. I now use Taylor Spiro Core....I recommend them over the Dyna wires.
I don't know if Dyna has changed vendors for the 2000 units/coils but I find the recent bad pieces disheartening. The new coils certainly look different than the older pieces.
There isn't much choice out there for ignitions....maybe an MSD box is the best solutiion.

[rktmanfj]

i also dont think a cold solder joint in the ignitor box would self heal either

My six years of experience as a bench tech says that they can and do sometimes regain continuity when the board cools.

Randy T
Indy

[fj1200d]

i also dont think a cold solder joint in the ignitor box would self heal either

My six years of experience as a bench tech says that they can and do sometimes regain continuity when the board cools.

Randy T
Indy

Totally agree with that statement. Tech's worst nightmare.

[racerrad8]

David,
       I am here to say the "module is bad". This is a common problem we see in our system DYNA makes for the Legends cars. They get hot and drop a coil and two cylinders.

Ohm out the coils and the pick-up coils and if they are good, it is the box. (Warm them with a hair dryer)

This is the one reason I will never use a DYNA system, they are highly prone to failure. Plus, when you use the DYNA system you are adding one more P/U coil to fail as well.

I have converted more than 30 Legend cars back to the stock ignition system from the DYNA system due to the high failure rates.

Oh yea and their theory the system "sensed" the "bad coil" is crazy. There is no feedback in this system to communicate upcoming problems; it smoked the board...

The one thing that always amazes me when I read someone change to the DYNA system and it runs better, is the fact they also changed the wiring.

The stock Yamaha wiring is adequate at best when new and as they age resistance takes its toll. If you make sure all of the connections are tight and do the coil relay mod to make sure the full battery power is there at the coils when you need it, the stock system will provide many, many years and miles of trouble free service.

I think Pat's bike runs great on the stock ignition as several people have told me the thing has great torque and I don't think it has even found its legs yet; Pat?

Randy - RPM

[Pat Conlon]

I think Pat's bike runs great on the stock ignition as several people have told me the thing has great torque and I don't think it has even found its legs yet; Pat?

Pat has not found his legs yet, let alone his bike..
The coil relay mod with fresh plugs, wires and boots works wonders with the stock coils...that 1349 motor, ooooh, I can't wait for my parts to arrive.

[JMR]

David,
       I am here to say the "module is bad". This is a common problem we see in our system DYNA makes for the Legends cars. They get hot and drop a coil and two cylinders.

Ohm out the coils and the pick-up coils and if they are good, it is the box. (Warm them with a hair dryer)

This is the one reason I will never use a DYNA system, they are highly prone to failure. Plus, when you use the DYNA system you are adding one more P/U coil to fail as well.

I have converted more than 30 Legend cars back to the stock ignition system from the DYNA system due to the high failure rates.

Oh yea and their theory the system "sensed" the "bad coil" is crazy. There is no feedback in this system to communicate upcoming problems; it smoked the board...

The one thing that always amazes me when I read someone change to the DYNA system and it runs better, is the fact they also changed the wiring.

The stock Yamaha wiring is adequate at best when new and as they age resistance takes its toll. If you make sure all of the connections are tight and do the coil relay mod to make sure the full battery power is there at the coils when you need it, the stock system will provide many, many years and miles of trouble free service.

I think Pat's bike runs great on the stock ignition as several people have told me the thing has great torque and I don't think it has even found its legs yet; Pat?

Randy - RPM

They failures I have recently encountered never even got hot! One on a dragbike, the other a new engine/brand new 2000 system. The dragbike had 12 runs on it and short dyno time. Do you have any experience with an MSD box (or anything else) Randy?

[SlowOldGuy]

Guys,
Thanks for the help. 
Frank,
I'm leaning toward a bad coil since I've had one before.  However, I'm still concerned about last time I had a "bad coil" and the entire ignition system shut down.  It's definitely the easiest fix.  I might be interested in sharing a set, but maybe we should consider Accel coils at this point?  I already have an extra set of Dyna coils.  In fact I've got a complete Dyna system sitting on the shelf for my '93, but I'm getting a little gun shy about installing it.  The install on the '85 was supposed to be a preventative measure to avoid these type of failures.  So far it's not exactly working out that way.  How about this experiment: You and I split the cost of a set of Accels, I'll install them and send you my "good" Dyna coil? 

Rich,
I can't solder to save my life, so all the connections are crimped.  I'll check continuity though. 

Randy,
I have an extra Dyna ignition box I can swap out if the symptom persists long enough to try that.  I agree that it's not logical for the box to detect a bad coil, but that's apparently what it did.  While everything was disassembled in front of the Honda shop, I swapped the ignition box and the pickup assembly and still nothing.  Only after I got it home and removed the coils (you can't accurately ohm them when the wires are hooked up) did I discover a difference in the ohms.  Once I replaced the offending coil, everything sprang back to life (until last weekend).  I'll go ahead and install the ignition relay (solenoid :-) but I'm a little concerned about putting a $5 relay in that harsh environment.  Is there a better place to access the coil power wire instead of above the hot head? 

DavidR.

[racerrad8]

I'll go ahead and install the ignition relay (solenoid :-) but I'm a little concerned about putting a $5 relay in that harsh environment.  Is there a better place to access the coil power wire instead of above the hot head? 

DavidR.

I ran a wire directly from the battery to the relay and used the stock coil supply wire as the signal to activate the relay. The relay was then grounded to the same lugs as the coil mounting which the paint was cleaned before the install.

I would use the $10.00+ relay, which I believe is 30 amp, as well as the molded factory plug to hook it up. I mounted Pat's to up under the fairing so it was out of the rain, but I wouldn't worry to much about the environment as they are sealed up pretty well.

Randy - RPM