Hi Trev, not in my fitting instructions?
Any chance you could send a copy of yours?
Would be most grateful
Ignition timing for twin plug heads
- Thread starter vince998
- Start date
Hi Trev, not in my fitting instructions?
Any chance you could send a copy of yours?
Would be most grateful
Hi, VInce, are your coils working one cylinder each, or sharing each? need to know this before saying more! Roy.
Hi Roy,
I´m running a wasted spark system so both ccoils are being fired at the same time.
I tried 1 coil for 1 cylinder (both plugs), but it runs like ***t
Have now one of each HT lead on each cylinder.
Spoke to Dyna and they said this is normal but couldn´t tell me why.
1 coil for 1 cylinder only when running single fire systems (seperate ignition pulse for each cylinder)
I think that you will find that the problem is that these coils do not have enough 'umph' to fire two plugs at the same time when both plugs are subjected to the high compression pressure on the firing stroke. Firing one under pressure and the other when there is very little pressure is all that they can manage. Whoever you spoke to should have been able to tell you this. Perhaps they had someone in on work experience that day!
I just remembered Steve Hamel has twin plugs on his Bonneville bike. I'll try to ask him about it and report back.
http://home.comcast.net/~gearheads/#anchor1
http://home.comcast.net/~gearheads/#anchor1
It seems to be standard for twin plug coils to fire one plug on eAch cylinder, Harley and BMW twinplug settle go down that route, some electronic ignitions require coils of a specific resistance, otherwise their seems to be a possibility of frying the electronics. I'm not sure if it is going to be too difficult to fire plugs on a 7:1 CR Vincent. Dyna Colour code their coils according to resistance and seem to be reliable in use. Other twin plug converters seem to use a variety of twin outlet coils from various jap bikes, goldwing coils are well spoken of. My (BMW) uses an ignition system made by silent hektik in Germany. It works well and has a variety of ignition maps to play with.
Hi time traveller,
This is standard practice on millions of Harleys running "dual fire" systems as well as a lot of other makes.
Even my yamaha only has 2 double coils firing four cylinders, so although each coil is energised seperately, each coil is still running "wasted spark" for its 2 cylinders.
Sorry time traveller, i´ve just re-read your post and realised you were talking about using 1 double coil to fire 1 cylinder.
You could be correct, but that doesn´t explain why it will work on single fire systems (2 pickups, 1 for each cylinder). The coils have (individually) the same work to do?
Thanks Bruce.
That would be much appreciated.
Only drawback is, Steve will almost definately have the bike set up for running flat out?
Hi Vince 998; I think that there is some misunderstanding here. If I understand correctly what is being discussed it is this. One coil, double ended or not will fire one plug in one cylinder when there is lots of pressure. One double ended coil will fire one plug under lots of pressure and, simultaneously, one with only atmospheric pressure as the low pressure plug will fire relatively easily. A typical double ended coil will not fire two plugs simultaneously when both are under high pressure. It is entirely possible that there are coils out there which will fire two plugs under high pressure at the same time but, if so, I do not know their make or model and this forum would be a good place for anyone who knows of such a coil to let us all know about it.