Electronic ignition

[Sesman]

Oh. I believe those hyper power drag engines employ magneto’s. Also very popular in aero circles too. 

[K2-K6]

Oh. I believe those hyper power drag engines employ magneto’s. Also very popular in aero circles too. 

Different reasons I feel. Aero was ordinarily mag, ultimately for reliability (useful attribute when your motor is in the sky) but Merlin for example is 4 valve.  Many use multi plugs to spread the flame front over a wider piston as I understand it, and so not so dependent on "herding" all the available stratified charge past the burn nucleus.

Drag motors etc are running very specific range of fuelling and fuels that lay outside general use. Also with two seperate mag and plugs duplicated on many to avoid full combustion failure. It's combustion failing to go or complete in this sphere that elevates the risk hugely.  Normally the "burn" starts and travels through to complete if possible.  Failure to complete leaves unwanted fuel sacrificial to detonation (uncontrolled and staccato explosion, rather than controlled burn ) that usually takes the cylinder with it in extremes.

[K2-K6]

Certainly I find this whole topic fascinating. 

But more than anything,  the engineers that did the original research and design of all these machines, I'm in awe of.

There's been some very clever people within these teams, trying to understand exactly what they did is intriguing.

[Sesman]

Yes, indeed. All very entertaining and informative.

[AshimotoK0]

Certainly I find this whole topic fascinating. 

But more than anything,  the engineers that did the original research and design of all these machines, I'm in awe of.

There's been some very clever people within these teams, trying to understand exactly what they did is intriguing.

Yes .. some clever stuff in the old  faulty Mk3 Boyer-Bransden black box (thanks JohnW  ) that I am just de-potting (with difficulty) I  was expecting to find a power transistor for each coil but no, just one big TO3 metal case device (sadly with no markings) .... Will report fully in Anoraks Corner in due course,  when I have fully de-potted it  and drawn out the circuit on CAD. No relay inside by the way and no chips just discrete components.

Oh sh*t Cathy just came in early and I have it boiling away in a pan on the kitchen hob 

[K2-K6]

 

[cbxman]

I’ve just seen a squirrel…..

Seriously though. I transistorised switch has got to be a better solution to achieve a superior Ldi/dt HT performance and reducing stored energy across the points Cdv/dt?

I’m betting that if CDI or and EI was available to Mr Honda back in the 70s he would have used it in preference to a mechanical system.

Just wondering….

Mr Honda did do just that.  The CBX1000 Z had EI right from the start in '78.  Three Reluctor Redundant spark system with three separate EI modules in potting compound mounted under the battery box.  These systems work very well and incorporate further electronic advance in addition to the mechanical advancer.  They are showing their age now and now there more modern aftermarket designs available from a Dutch specialist.  Not cheap though!!  The later "B" and "C" models used the same modules but not potted and mounted individually.

Cheers,
Jerry

[Oddjob]

I am replying for Ash as he's now been sent to bed with no supper and banned from the internet for 3 weeks. Damn Cathy is a hard woman.

[Nurse Julie]

Certainly I find this whole topic fascinating. 

But more than anything,  the engineers that did the original research and design of all these machines, I'm in awe of.

There's been some very clever people within these teams, trying to understand exactly what they did is intriguing.

Oh sh*t Cathy just came in early and I have it boiling away in a pan on the kitchen hob 

Cathy doesn't mind you boiling your bits on the hob Ash, she told me so 😂😂😂😂

[Sesman]

Still think mags are the best. They have worked very well for 61 years on my primitive T110.

[Sesman]

Just kidding ..

[AshimotoK0]

I found this which answers my question on the Boyer Bransden system. It only has a single transistor because it fires all 4 coils at the same time. .. so I guess consumes double the current of the standard ignition

http://www.sohc.co.uk/index.php?topic=9062.0


Also found this where a Norton guy de-potted a BB unit. :-

http://atlanticgreen.com/boyerexposed.htm

The Honda 4-Cyl Mk3 one which one I am de-potting has blocking diodes on each coil though and a string of 5 series connected Zener diodes, which protect the transistor. Still plotting out the Honda-4 version circuit. All of the capacitors are tantalum type.... which is good news.

[Oddjob]

Ash, reading that Norton BB post made my head hurt. Shame on you picking on an old man.

My Hondaman ignition module arrived today  . Only fault is there are no holes in the circuit box to attach it to anywhere, I'll have to make a cage for it to hang it off the back of the battery box.

[Johnwebley]

I found this which answers my question on the Boyer Bransden system. It only has a single transistor because it fires all 4 coils at the same time. .. so I guess consumes double the current of the standard ignition

http://www.sohc.co.uk/index.php?topic=9062.0


Also found this where a Norton guy de-potted a BB unit. :-

http://atlanticgreen.com/boyerexposed.htm

The Honda 4-Cyl Mk3 one which one I am de-potting has blocking diodes on each coil though and a string of 5 series connected Zener diodes, which protect the transistor. Still plotting out the Honda-4 version circuit. All of the capacitors are tantalum type.... which is good news.

Brilliant,

Sent from my SM-A750FN using Tapatalk

[Green1]

Been having trouble with my 550 for ages now not firing on all four. 1&4 refuse to fire. Tried swapping the blue and yellow wire and no change.
I have replaced coils,leads, caps and plugs. They all test fine.
Put a new battery in awhile ago. In the wrong way round. Resulting in me striping the main loom to look for damage. No major damage other than a couple dodgy old repairs and a few corroded cables now cut out and replaced and burnt harness behind the fusebox now replaced. Must have made a difference as the lights are clearly a lot brighter and 2&3 have a bright blue spark. I've tested the Boyer Branden and confirmed over the phone with them it must have been damaged when connecting the battery the wrong way. New BB and still no spark on 1&4.
The only thing I can think of now is the stator must have been damaged as that's the only other thing I can think of that would control the spark.