Topic: Dyna III & coils. Like a snowball downhill...

[dt77]

I have recently picked up a ’77 CB550K.  To my surprise I discovered a DYNA III ignition.  OK, that’s a bonus.  But it doesn’t start.  I figured since she sat for over a year, I should clean the carbs out.  I removed and rebuilt them per this site, salocal, oldmanhonda.com, the 550 manual… still no start. 

I test the plugs.  Spark on 2 & 3, but not on 1 & 4.  I switch the leads at the coils and I have spark on the 1 & 4.  So the coils are OK?  I did a search on this, but some say coils are OK and some say not.

I traced out the blue wire (from the 1 & 4 coils) and I test all the splices with a test light.  It’s good at all splices.  Now I’m starting to lose it. 

I traced the yellow wire (2 & 3 coils) with the test light and it doesn’t light up at the splice before going into the Dyna III ignition.  What?  I thought the blue wiring from the 1 & 4 coils was the issue.  I take a few days off.

I ease back to my garage to find NO voltage @ the coils?!!  So the coils are shot.   Right?  Wrong?  I really do need some positive reinforcement now. 

This is my virgin rebuild.  And I’m beginning to think the priesthood is not such a bad thing…

But I did do various searches in the forum.  I sure the coils are shot, but what of the Dyna III.  The yellow wire was showing voltage at splice before the Dyna when it was open, but when I close the splice, it shorts out.  I also replaced the splices leading up the Dyna III.

Any news is good gnews.

[Patrick]

Check continuity through your kill switch.

Patrick

[trinorman]

Also try the Dyna website for assistance: 

http://www.dynaonline.com/english/index.htm

And directions for installation from the same site:

http://www.dynaonline.com/english/instruct/DS1-1_1-2.pdf

And there is tech help available too on the site.

Good luck!

[Lumbee]

...drop the dyna and throw a points plate on it just for a sanity check...

[TwoTired]

May I suggest that part of the problem is a general flail instead of a methodical troubleshoot approach?

Perhaps you'll try this?

1- Disconnect both the Yellow and Blue wire at the coil.

2- Check Black wire TO the coils with the key on.  Red probe on Black.  Black probe on a green wire or engine case where there is no paint.
If you don't have Battery potential (12V) or very close to it (do a compare to that at the battery terminals), the coils and ignition can't work.
Then fix the problem here.  Otherwise...

3- Reconnect the Black wires to the coils.  Now measure the disconnected Yellow and Blue wires each with the red meter probe and the Black probe on a green wire or engine case where there is no paint.
Again you should have Battery potential (12V) or very close to it.  If not, and you had voltage at the Black wire on the previous test, the coil(s) is bad.

4- Next lay #4 connected spark plug on the motor or wherever the spark plug body can touch a battery return path (engine, frame, Green wires, etc.)  With an extra wire, used as a temporary jumper, bridge the Blue wire to engine, frame, Green wires, etc.  Each time you remove the jumper, the spark plug should spark at the gap.

5- Next lay #3 connected spark plug on the motor or wherever the spark plug body can touch a battery return path (engine, frame, Green wires, etc.)  With an extra wire, used as a temporary jumper, bridge the Yellow wire to engine, frame, Green wires, etc.  Each time you remove the jumper, the spark plug should spark at the gap.

If you got the plugs to spark, you can rule out a coil problem and focus on a DYNA issue.  If not, there could be coil, lead, plug cap, or spark plug issues.

6 & 7- Assuming tests 4 and 5 were positive, reconnect the Yellow and Blue wires at the coil, and find out where these wires connect to the DYNA.  If you can disconnect there, repeat test 4 & 5 with the wires that would have connected to the Dyna.
If you still got plug sparking, most likely the DYNA or its attachement electrically to engine, frame, Green wires, etc. is compromised.  If not, you have an interconnect problem between Dyna and coils which you must track down and correct.

I still use points.  So, I can't help with the repair of a broken DYNA.

Cheers,

[Patrick]

DT, I suggested the kill switch may be the problem because of an issue I had a couple years ago. My 1975 CB750K would not start. I pulled a plug and found no spark. Figuring the worst immediately, rather than checking the obvious I starting tracing the wiring. I had no juice on the yellow or blue wires coming from the points to the coils. But I found something interesting. When I unplugged the blue wire, I had juice on the yellow. When I unplugged the yellow wire, I had juice on the blue. When both were connected I had nothing. Then I checked the kill switch. It was off. I flipped it on and rode away.

If one of your wires was broken it would be the same as if one were unplugged and you would have juice on the other. Try disconnecting one wire and see what happens.

As I am a tinkerer and not a master, like some folks on this forum, I could be full of s**t or my memory could be faulty. But that's the way I remember it. It's easy enough to try.

Patrick

[TwoTired]

No offense meant to Patrick. 

But, I'm afraid if you follow his T/S proceedure, you will likely get more confused.  While it is a good thing to check your kill switch, it interrupts power to both coils.  If you got one side working for spark, most likely the kill switch is not the issue.

On a points system, contact closure completes a circuit to engine ground.  I don't want to get into a current flow debate (plus to minus or minus to plus), but most of us think of power routing of the positive terminal.

I suspect Patrick might have been confused by the state of the point contact closure.  The ignition circuit has multiple circuit interupters. The ign switch, the kill switch, and the points contacts on a stock bike.  Further, juice is a rather imprecise term, and makes no reference to where the test probes have been placed, which can be critical.

Best regards,

[dt77]

Thanks for the great advice!!!  Unfortunately, It's been wicked cold here in Chicago!  We've been in the teens or 20's.  Add a Lake Michigan wind chill and...brrr.  I've already printed out the advice and I'll tackle the issue as asson as I get the gumption to brave the elements or drop some $$$ on a industiral space heater.  Thanks again.

[burmashave]

May I suggest that part of the problem is a general flail instead of a methodical troubleshoot approach?

Perhaps you'll try this?

1- Disconnect both the Yellow and Blue wire at the coil....

TT, I'd like to nominate you for the clear, concise and comprehensive response award.

[dusterdude]

May I suggest that part of the problem is a general flail instead of a methodical troubleshoot approach?

Perhaps you'll try this?

1- Disconnect both the Yellow and Blue wire at the coil....

TT, I'd like to nominate you for the clear, concise and comprehensive response award.

yea,he`s the man.

[DrMark]

TT, That was Hands-down the best explanation I have read on troubleshooting a Dyna problem. Concise and simple. What probe, where it goes and expected results. Thanks for taking to time to help a electrically challenged member with a new digital multi-meter from Santa. Can you do the rest of the bike now? (I'll save them all - I promise).....just kidding. Thanks, DrMark