Another coils post

[Guest]

So I ordered and installed what were listed as dyna coils on ebay. What I got appeared to just be some no name China coils but I stuck them on anyway. Question is, since I've seen it somewhere before but can't find any trace of it, can cheap coils cause a loss of power when under load such as accelerating at highway speeds?
Between the coils and the worn out air filter(I have one ordered) I'm at a bit of a dead end.
To top it off, the listing I bought from has changed the title to reflect that it was just an "aftermarket" coil with no brand name listed.
1981 650G
Already cleaned and adjusted carbs, new plugs, full charge on the battery. Plug chop looked a little dark but not caked or wet, was assuming it was due to the air filter being collapsed and coils possibly misfiring at high loads.

 

[Nessism]

What's the primary resistance of the coils you purchased? Your bike is designed to use coils with between 3-5 ohm resistance.

 

[Guest]

It might be worth mentioning that I have the dyna s ignitor installed. Will that make a difference in the coil requirements?

 

[zed1015]

With a Dyna S you want 3 to 5 ohms coils as Nessism already confirmed and your stock ones would have been suitable although wouldn't have had the increased output of genuine DYNA ones.
I've seen the Dyna copies you describe and although i've not had experience of those particular ones myself i have a friend who has recently bought some green 3 ohm's for comparison tests a few months ago and so far they are holding up and check out and function exactly the same as the Dynas..
Apart from the lack of the DYNA name they seem to be identical in every other way and it's even possible that they are made in the same factory.
As for your power loss then yes! any sort of poor electrical contact , short or breaking down under load will cause loss of power as you describe..
If you your original coils were not faulty then try re-fitting them to see if that cures the issue and if it does you should surely be able to return the fake ones for a refund..

 

[Guest]

Primary ohms out at 4.3 LH and 4.0 RH connections feel snug, no corrosion on the pins. These aren't marked for +/- like the OE ones were. Could that make a difference?everything is wired up exactly like the old ones came off as in the +/- wires and spark wire locations.

 

[Guest]

Primaries on old coils is about 3.8 and 4.0..
Secondaries on new coils is about 34k ohms without caps installed, old coils about 11.5k. Caps are about 10k each, caps that came with new coils are damn near 0 ohm but they are all shorties and won't reach the inner cylinders.
I looked into it further and it turns out that for whatever reason Google defaults to caltric brand coils when I search for dyna. They have non removable leads so I can't really pull the wires and test directly at the coil secondaries. I think I'll just reinstall the old ones and see what she does.

 

[Guest]

I totally thought I had it pinned. I found a rock jammed into the air filter box drain hose. Don't know how or why it got there but as soon as I pulled it out I had old fuel dump out all over the driveway, likely there from when the petcock failed a couple weeks ago. Drove like a bat out of hell for that 1st ride. Shut off and played with the dog for a little bit. Hopped back on and there's that odd lack of power again but a bit more intermittent than before.

 

[Guest]

FWIW
A few years ago I had a frame powder coated, after reassembly it had weak spark. I ran a ground wire between the coil mount bolts and then to my central ground. That took care of my ignition problems.

 

[salty_monk]

How much voltage do you have on the orange white at the coil? If less than 11v do the relay mod. Personally I would do it anyway. Simple enough and protects against future degradation.

Run your bike at night and wiggle the plug wires about, sometimes they split and you lose spark to the head but only when the split opens up under load from wind etc.
at night you should be able to see the fireworks...