Series D Distributor wanted because Boyer quit, again.

[Simon Dinsdale]

Just posted this on another ignition thread:

Tracey,

Go points / coil ignition. That is what I use except mine is a home made unit. Uses a pair of Ford points which are identical but mirror image. Each points on a seperate slotted carrier so the timing of each cylinder can be set seperate and two condensors and coils so each cylinder is totally seperate apart from the battery and ignition switch. Timing advance is done by an original magneto ATD in the timing cover. Only problem I have had is the occasional condensor failing approx once every 5 years. Spare condensors are easy to carry and take 5 minutes to replace. In fact on mine the condensors are now mounted under the mag cowel on a bracket with a spare also mounted so it is just swap the connector over if needed. I also use two small Triumph / Norton coils (or could use a twin output coil) so you can also get rid of the distributor cap and rotor.

I tried the modern electronic method and it failed at a rally. That was the only time I have had to be relayed home due to ignition. Never again. Reliability and the ability to fix on the roadside if required is everything in my opinion. If an electronic system fails then you are stuck and if you follow the forum then you will see that a lot of people are having failures on electronic ignition across a lot of the different systems. Alright points / mechanical timing are crude, but they work, and lets admit the engines are an old slow reving design that don't really need the technical timing advantages a modern engine needs to pass the modern emmissions / legistation.

Hat on awating the flack.
Simon

 

[bmetcalf]

mine is a home made unit. Uses a pair of Ford points which are identical but mirror image. Each points on a seperate slotted carrier so the timing of each cylinder can be set seperate and two condensors and coils so each cylinder is totally seperate apart from the battery and ignition switch. Timing advance is done by an original magneto ATD in the timing cover. Only problem I have had is the occasional condensor failing approx once every 5 years. Spare condensors are easy to carry and take 5 minutes to replace. In fact on mine the condensors are now mounted under the mag cowel on a bracket with a spare also mounted so it is just swap the connector over if needed. I also use two small Triumph / Norton coils (or could use a twin output coil) so you can also get rid of the distributor cap and rotor.
Simon

Did you make your own cam?

 

[Black Flash]

Hello Simon,
the only bike I had I rode a considerable mileage with and that I kept for quite a few years using it was a 750 CC Commando S-type. Commandos are well known for rattling their ATD to pieces. I installed a boyer unit using the old coils that were on the bike from day one and the system performed faultlessly all the time I had it. The guy who bought it from me had the bike for another nine years and never had to change anything or retime it whatsoever.
only problem ( well known by the way) is that the system is critical with voltage. Starting on a low batterie always produced massive backfiring and flames out of the exhaust.
I was always happy with the system and NEVER had any problem

 

[Tracey Tilley]

We have had the box fail on our Commando. Chris can provide more details, later.

 

[Black Flash]

Regarding my Commando, this was still the old type of box, not the "micro digital" system they now sell. It definately lasted 15 years at least,.
Maybe I was just lucky?!

Bernd

 

[Tracey Tilley]

Apparently it never ever stopped dead on the Commando. It usually popped or spluttered but always got him home.

We have had 3 boxes stop completely on the Vincent. No warning just no ignition.

I even told the guy on the Boyer technical helpline that it was extremely unreliable and we always carry a spare. He made no comment.

 

[Simon Dinsdale]

Did you make your own cam?

Yes. Using two sets of points on slotted carriers allows you move each points seperately in an arc around the shaft and set the timing on each cylinder seperately. The Ford points been identical but mirror image of each other allows you to get the heals of the points closer together on the arc around the shaft (as against 180 degrees on a vertical twin) to allow for the twins 50 degrees between cylinders. Then the cam only needs one lobe which is easy to make. Its the points position and the use of two points that allows for only one cam lobe.

I am not saying that the principle of electronic ignition is faulty, but there seems to be a lot of discussion of units failing on this forum. Norton Commandoes may rattle their ATD to pieces, but they are on vertical twins which are known for vibration.

Electronics on modern cars go through a very costly design and development process with testing and designing to pass very harsh enviromental tests. These tests been a very big costly exercise. I cannot believe somebody selling electronic modules for classic bikes in the quantity of hundreds per year will have subjected and developed their designs to such enviromental shock / vibration / thermal / humidity etc where the costs of testing can go into £thousands per day to British and Euro standards. I worked for a company that produced a microwave sensor based car alarm. The design and enviromental development cost were £200,000+ where the acceptable failure rate was a lot less than 0.01%. I bet a lot of electronic ignition units for classic bikes never went through this design process. If they had, the current discussion about failures wouldn't be happening.
Most if not all new cars now days use modern electronics. Yes a few may fail, but most don't and their production runs are larger than aftermarket ignition units for classic bikes.

 

[Bill Thomas]

Hello Simon, I prefer the D setup because it only needs 1 coil, 2 coils twice the power needed ?, I have had trouble with the small coils so only use big ones, I spoke to price productions a few years ago and he said there would be no trouble with supply !!, Short of cash at the time,whished I had got them then. Like a Twit, I sold a twin points setup a few years ago, I could have used it on the Comet !!. May be someone in France will make them ?, Good luck, Bill.

 

[Simon Dinsdale]

2 coils twice the power needed ?

Hi Bill,

It's all down to the duration the points are closed / open. On my twin points setup due to the cam profile only one set of points are closed at any one time and so only one coil is drawing current (power) at any time. So on one full rotation of the shaft / cam each points close for approx 30 degrees (this is a guess not accurately measured) so each coil draws current for 30 degrees.
On a single coil and distributor for a twin, the cam has two lobes. Each lobe will most probable open and close the points for approx the same duration as the points in the above twin set up, but the distributor has two lobes so the distributor points open and close twice per shaft revolution to fire both cylinders and so the actual power consumption is the same. In a distributor the points are doing twice the work each seperate points do on a twin points setup.

Easiest way to see it is to watch the ammeter when slowly turning the engine over with the ignition on two seperate bikes where one bike is twin points setup and the other a D distributor. There will be no noticeable difference in current draw and duration as long as you turn each engine over at about the same rotation speed.

Hope the above makes sense.
Simon.

 

[Bill Thomas]

Sorry to hijack this thread,Nice little video of a Vin on Avon tyres, www.motorcyclenews.com Cheers Bill.