ET: Engine (Twin) Old Coil Ignition Points Identification

Rob H

Well Known and Active Forum User
VOC Member
Hi all, I have an old coil ignition system on the bike and looking to replace the points but have no idea what they are or where to get some. I am guessing they probably used some readily available car points but what ones? Anyone familiar with this system?
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Monkeypants

Well Known and Active Forum User
Non-VOC Member
That looks to be the same system as I have on my well used Rapide.
When I bought the bike, the Australian seller , who had owned the bike ten years and ridden it for about 20,000 miles, said " You are going to love the electronic ignition on this bike. 1 kick starting every time."
The second part was true( nearly)
Apparently he had never lifted the points cover.
Things I have learned about this setup-
1. Never use pattern replacement points. Always use original genuine Lucas new old stock points.
2. Lucas points are capable of lasting a very long time. They are not like the old North American automotive points of the 60s/70s.
One set can go for 50,000 miles. I'm working on that!
3. The starting with this setup is ridiculously easy.
4. A points gap of 15 thou will get you ignition on one cylinder only.
That close of a gap ends up robbing the coil for the rear cylinder.
I encountered this problem by accident after removing perfectly good Lucas points then replacing them with Japanese Daichi pattern points.
I started with a 25 thou point gap at home and ended up with about 18 thou and running on one cylinder 400 miles from home. We had the best of the best Vincent experts on hand and they tried very hard to sort it out, but without being familiar with that system- it was decided to haul the bike home as cam timing must have slipped.
The 18 thou gap looked right to anyone familiar with magnetos.
It's not enough for this system.
Next day I more or less discovered this by accident when my truck transport vaporized and I was sitting looking at the bike.
I noticed the gaps were much smaller than I had set them at home, so I opened them up.
It fired right up on two cylinders and ran great most of the way home. 75 miles from home it went back on one so I opened the points a bit and away it went on two again.

After that I tried to corner the market on NOS Lucas points.
I have enough on hand to run for a quarter of a million miles or so!

That's about all I know about it except Ill add that the bike goes like hell, better than it should on paper, maybe that ignition is part of that?
Glen
 
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vibrac

Well Known and Active Forum User
VOC Member
To the coil ignition ignorant opening the points may do something electrical but it certainly moves the ignition point earlier perhaps resetting that and reverting to 15 thou would have had the same effect and given the system an easier time, but what does a BTH acolyte know?
 

Peter Holmes

Well Known and Active Forum User
VOC Member
Know Thy Beast states 12 thou points gap for the Series D Lucas distributor, seems to work fine on my D Comet.
 

roy the mechanic

Well Known and Active Forum User
VOC Member
Glens story sounds familiar. The points close due to wear on the heel , this can be reduced dramatically by applying a small ammount of h m p grease to the cam. Also as there are two sets of points,I would recomend using two condensers. I could say why, but it would need around 3/4 of an hour to trypewriter it up.
 
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