DYNA III ignition: why a 'F' in the timing hole at idle?

[Rohls]

Hi,

I am having trouble setting up the DYNA 3 ignition on my 1977 R75/7. I can get it to run, but only after a year of trying the find the sweet spot on the magnet....grrr...really frustrating.

I can now have it idle, albeit at abour 1500 RPM.

I checked the timing hole and it is showing 'F' as in fully advanced. I cannot for the life of me get it to retard to 'S' as in static timing.

Ever move I make with the rotor/magnet and base plate causes it to do the same thing of not run anymore.

I even tried switching back to points, but those are simply not working, I guess I stepped on my own d&#k here....frustrated.

The dyna instructions say to '..bend the spot welded tabs on the back of the $282 advance mechanism..." i don't think that is correct...anybody ever do this?

Please help

Thanks--happ y new year!

[PITAPan]

Hi,

I am having trouble setting up the DYNA 3 ignition on my 1977 R75/7. I can get it to run, but only after a year of trying the find the sweet spot on the magnet....grrr...really frustrating.

I can now have it idle, albeit at abour 1500 RPM.

I checked the timing hole and it is showing 'F' as in fully advanced. I cannot for the life of me get it to retard to 'S' as in static timing.

Ever move I make with the rotor/magnet and base plate causes it to do the same thing of not run anymore.

I even tried switching back to points, but those are simply not working, I guess I stepped on my own d&#k here....frustrated.

The dyna instructions say to '..bend the spot welded tabs on the back of the $282 advance mechanism..." i don't think that is correct...anybody ever do this?

Please help

Thanks--happ y new year!

If you assume the instructions from the mfg. are incorrect, what chance does some stranger on the internet have? Or a better question might be should they have any chance at all? That said, if you spent a solid year getting it running it all you have remarkable perseverance. Others would have given up long ago and heaved the silly thing.

1) Are you checking the timing with a strobe light?

2) What kind of strobe light?

3) At what RPMs are you checking timing?

4) Is this a new Dyna or an old used one?

5) Is it magnet and coil or magnet and switch? (I forget, I think the Boyer is magnet and coil, I hated the Dyna in the end and after 2 never got another).


6) Is the gap between the magnet and the whatever adjustable?

7) Is the bike dual plugged?

8) Have you had the flywheel off or worked on the timing chain?

If you can't get it running on points (single plugged) I would back up and correct that. You will need to do this and you will need to carry your points plate, condenser, spare points and a points file under the seat for when, not if, the Dyna craps out. On a new Dyna I would put the spares in a vacuum seal bag so they stay good, it will be awhile. The other reason for the points is you need to understand the ignition system cold and it all needs to be working. If you can't get it running on points, something is wrong either with the system, your understanding, or both. You wanna fix this. if you over run what you truly understand, you can get extremely frustrated---in small part because in the very back of your mind you know you have been hasty and overstepped your self---personally I really hate doing that.

[Kurt in S.A.]

I'll admit the Dyna III is a bit fiddly, but there really should be no reason you can't get it to time properly. I recently went through a round of this and got it pretty close...the strobe shows a slight double image that I want to correct.

There are at least 3 degrees of freedom when setting the timing with the Dyna III...that's one more than a standard points set up. The backing plate will rotate left-right as you look at it from the front. Each of the coil pick ups can be moved circumferentially and independent of each other (that might be 2 DOFs right there). And the donut on the advance unit shaft can be rotated completely around the shaft. You have to find the sweet spot amongst all this.

Here's what I would do. Get the backing plate mounted more or less in the middle of it's range. Then, with the plugs out and tied so that the threads of the plugs are touching the engine's fins, turn the ignition on, and rotate the engine in the proper direction using the alternator bolt. Watch/listen for the snap of a plug firing. Look where the magnet is on the donut relative to a coil and then look at the timing mark in the window. IIRC while looking at the front of the engine, the left coil will control the firing of the plug on your left on the compression stroke. Then, without changing anything, rotate the engine 360 degrees, anticipating the snap for the next cylinder. Recheck the donut position relative to the other coil and also the timing mark.

At that point, you should have a better idea of what to change. You might need to make a large adjustment with the donut and then do some individual adjustments with the coils. Once you get the snaps to occur at the proper time (S-mark in the window), then button things up and use your timing light to check things while running. I left the front cover off and used some tape to hold all the wires to the case so the advance unit didn't accidently cut them.

Probably one of the last things you could do is rotate the backing plate, but of course that changes the timing for both firings equally. You might need to do that at some point in order to give back some adjustment room with the coils/donut.

It's fiddly, but it's doable. I have never had to "bend" a thing...I wouldn't do it.

Kurt in S.A.

[Rohls]

Thanks for your replies; very informative. I'll try to answer the questions posed...

1) Are you checking the timing with a strobe light?---Yup, the same one I've used recently ro time my R90, so I know it's at least kinda close.

2) What kind of strobe light?---not sure, nothing fancy.

3) At what RPMs are you checking timing? the 'idle' RPM is 1500. This is the lowest I can get it right now and not have it cough out and die. I recently went through the carbs, and they are clean. New parts in there, circuits blown out with compressed air/B-12.

4) Is this a new Dyna or an old used one?----Brand new. Kinda wonder if it needs to be adjusted outta the box. Welp, strike that, I know it needs to be, but not sure how

5) Is it magnet and coil or magnet and switch? (I forget, I think the Boyer is magnet and coil, I hated the Dyna in the end and after 2 never got another).--I believe the rotor (donut that slips over the points' cam) has the magnet in it and the coils are adjustable 'moon' shaped things. One for each cylinder.


6) Is the gap between the magnet and the whatever adjustable?...Yup.

7) Is the bike dual plugged?---Nope.

8) Have you had the flywheel off or worked on the timing chain?---nope. It has 68000 miles on it, and I'm pretty sure it's never been cracked open....



I've recently switched the bike back to POINTS. the plot thickens. I now get NO SPARK (!). Couldn't believe it.

First question---I know it is simple, but what is the basic connection of the points/condenser/coils/ground/battery? I had to take wire in the Dyna, and the manual wire diagram seems to be missing a wire...hmmm.

What it the resistance of the coils supposed to be? Is the Clymer manual values correct? I am getting 6.3 K-Ohms at the secondary coil (reading between the high tension spark plug out and the positive terminal (+15 on the Bosch coil). I'm getting ~2.1 Ohms between 1 and 15 terminal on the coil.

THANK YOU KURT for the reply. I will adhere to your advice when I switch back to the DYNA.

Thanks again...

[Deleted User 62]

Swiped from Duanes website:

[Rohls]

Thanks!

So what about the coils' resistance values?

[PITAPan]

Thanks!

So what about the coils' resistance values?

I looked at the Dyna III installation instructions: 3 ohms. primary resistance. That would be total for both your coils measured with them connected.


Can you return that Dyna? Wadda mess...(almost as bad as their website)

[Duane Ausherman]

You must make it run on the original system first. Then, only then install the Dyna. Take a look at that super simple diagram of the ignition system. (That pro cad drawing was done by our South African friend)

If the resistance is off by a bit, it will run, but maybe not correctly at high rpm.

You mention that it idles at 1500 rpm. If it won't run at 900 rpm, then you have a problem, fix it. Did you do the 5 second test to see if the high idle is caused by ignition, or fuel? I have an article on this issue.

When I am in a similar situation and vexed with frustration, I take a break and then go back and examine all of my assumptions. You may not have consciously assumed something in error, but I bet that you are assuming something is OK and it isn't ok. Long ago I lost count of the many times I made that error while working on these bikes.

Tim, thanks for the credit, but it isn't necessary. Anyone may lift whatever they wish, it is all public. The only reason I like credit is to advertise that the information is there.......... for everyone to use.

[Zombie Master]

With that kind of mileage I would wonder if you timing chain is loose?

[Rohls]

Roger that. I'm on the path to get it going on the points first, then switch over o the Dyna if the trash man hasn't taken them by then...

What about the secondary resistance to the high tension (spark plug) lead? I'm getting ~6.3kOhms @ about 55 degrees ambient temp...? Is this really important to be higher (like 7 or 10 kOhms) per the manual?

Thanks again for the help! Much appreciated.