Forum

[Count Johnny]

So, Scalyback. I'm on the right track - in terms of understanding this phenomenon - but with ar*se about thinking and rubbish maths.

[Norm]

Gwilly, I'm now to scared to go and start my Enfields because of all the collisions etc going on inside my coils. Life was simple once when I just hooked up a couple of wires to my coil and I had spark. I will never be able to ever look at my coils again without all these visions going through my mind. I think I will have to lay down for a while

[Alan R]

in that case NORM, take this along for a little "easy reading" }----------- http://en.wikipedia.org/wiki/Capacitor ----------

[Scalyback]

Denis C, well I sort of forgot, my last engine was a 1924 Lister with ML- MCK magneto which I had to get from a parts jumble. Saw the hen's teeth MCK, grabbed it quick and gave the sprocket a flick. Screamed loudly, bought it, and it had worked fine ever since! I think there is a capacitor in there some where, but i only set the timing and points!

John-L, If i'm explaining it, chances are it will go round and round until even I forgot what point I was trying to make. therefore 'hypothetical' sinks lower and lower until it becomes 'hypo-pathetical', or 'beneath pathetic'.


CONCLUSION (worth a try...)



Remove spark plug, leave HT lead connected to the top of it, rest body of plug against engine but so that you can see spark plug gap and turn the engine over. If you see a nice blue spark then put plug back in, Jump in the air, kicking your heels together whilst shouting "Scroombana", get on your bike and ride in the blissful ignorance of how it works, but with the happy knowledge that your bike works well!



"Turn right four times, that brings you back here, then ask again!"

[Alan R]

Hello SCALY-----------yes, even magnetos have a capacitor within them ( or sometimes outside as I indicated earlier ).....Now you're getting the right idea Re}--- How it works etc. and as you ( and I )have said}-- Nice blue spark, good "crack" sound, and then put the plug back and let the THEOLOGIANS fret over the actual working.Meanwhile get out on the road and .......................RIDE !!

[Dennis C]

"Turn right four times, that brings you back here, then ask again!"

Errrrrr, what was the question?. Also loosing the will, if the spark ignites the mixture thats all you need.

[Frank]

If we are talking about a bike with a working charging system then doesn't the rise in voltage as the revs increase also need to be factored in? Taking the 3.8 ohm coil with a good battery with engine off the drain would be 12.5/3.8 = 3.29A. On tickover with minimal charge say 13v and taking the 20% points closure period then the average drain would be 13/3.8 X 20% = 0.684A. At higher revs with a full charge voltage of say 14.2V then drain would be 14.2/3.8 X 20% = 0.75A . Whatever the % of points closure the trend would be for the current to increase with the revs until Max charging output voltage. Am I missing something again? Can't all this speculation be verified by connecting an ammeter to the coil and measuring what the current is at various engine speeds?

[Scalyback]

YES !, Go poke it with an ammeter!

[JTL]

Dennis C and Scalyback, thank you for your answers. It makes me think about some more questions just to clarify a little more about coils... So the inductive ignition systems covers the points system (I run points on my bike). Which means the Bullet needs a coil 3 to 4 ohms (primary resistance) to keep the points in proper condition for a longer time. Can the coil have a too high secondary resistance or a too high voltage output to the spark? Protecting the points is one thing, but should we also think about protecting the plug? If so, how to do that? Jacob

[Alan R]

Hi guys--------------Please do take time to have a look at this, and in particular the section about the capacitor's function with relation to spark intensity.....They use the word "oscillate" to explain what I was trying to put over earlier... http://en.wikipedia.org/wiki/Ignition_system ..............Incidentally my Apprentice Training notes were provided by Lucas Electrics, who also set up the simple demo. rig that I asked you to try out....