I don't like the Dyna coils. In the 90s I had fallen victim to Dyna's bragging about 36kV or so. They look robust, but, being a generic product, the weakness is in the - not tailormade - connections. Moreover, for a CB500/550 I find them too bulky (see pic). That high voltage is not needed as these coils will spark at the same voltage (~ 7-9 kV) as the stock coils do and as long as you're not dragracing a highly tuned bike, you can ignore Dyna's bla. Let's have a closer look at the connections. Wires are not included so you have extra costs buying the Dynatek DW-200 wiring set. You yourself have to crimp the connectors that go into the towers and it depends on how good you're at it, to do it succesfull. On these bikes, there's not much room for an alternative routing and this results in quite a hassle. Little rubber caps come with the Dynatek wireset, so everything is nicely shielded against moisture. However... these caps become rock hard after some time and will be extremely hard to remove and put on again. At first I was enthusiastic about the silicone plugcaps. Not anymore. Nothing wrong with silicone - on the contrary - but these caps lack a resistor, so R plugs are required to be streetlegal. I'll come to them later. Furthermore Dyna has chosen connectors that require a ferrule on top of the plug. Why? I don't know. NGK caps connect way more solid. More than once, forsaid ferrules have come loose. The silicone Dynatek HT wires are very supple and although I like that in general, here they can move about quite a bit in the riding wind; not favourable for robust connecting.
In Europe professionals that work on our CB Fours on a daily base, advise not to use R plugs and although I first ignored this as nonsense, I have come to the conclusion that R plugs and our bikes is not a good match. I have too many R plugs lying around now that gave up prematurely. BTW, I have noticed that Denso R plugs, increase their resistance over time and NGK R plugs seem to decrease. Why this is? I don't know. Maybe it's just my experience.
Just the other day I have replaced the Dynatek plugcaps by new NGK resistor caps and also replaced the dreaded R plugs by conventional NGKs. I noticed how well the NGK caps connected to the plugs and after I had started the engine, a miracle seemed to have happened! I realised I should have done this long before. I had been stubborn not to accept the knowledge of professional mecs, not without any further substantiation to their findings.
To do my further testing correctly, I will - for the time being - run the Dyna coils, but as soon as another issue occurs, I'll abandon them and the old OEM coils will be on again. After all these years they still give the right spark and they are a direct fit. They would be perfect, if only you could screw on new HT wires, the same way you screw on caps to the wires. I have seen aftermarket coils that have this, but not recently. On the other hand, repro's are relatively cheap to replace.
Note however that also the Sakura coils have the wrong connector towards the points: a male where it should be a female. It seems all aftermarket coils have this. It means extra work fitting them. I hate extra work. Why PartsNmore does not suggest these for the CB500/550, I don't know. Maybe it has to do with the different windings ratio the OEM coils have (CB750: 380-15.000 and CB350/500/550: 420:13.000).
Here a tip. When you pull the plugcaps, make sure your hand cannot travel too far in a brisk movement, compromising the connection!
