What am I looking at?

illf8ed said:

I’m using a TriSpark now, but would love to have a working RITA for when the TriSpark dies.

Click to expand...

That is what i am saving my RITA AB11 for...knock wood.

One thing i have to say about my RITA, it always functioned flawlessly with a knackered old battery.

kommando said:

Boyer, under pressure from the Pazon not being so voltage sensitive, introduced the Boyer MK4, so its the Boyer MK3 that has the issues with advanced timing from low battery voltage. The MK4 does not but still has its foibles like the wires to the stator being vibration sensitive, the Pazon and its foible of the extended wake up sequence which makes it unsuitable for high compression singles.

Click to expand...

I do find the Boyers a bit confusing as there seems to be three current variants, but what are the differences ? Their website isn't clear.

cliffa said:

what are the differences ?

Click to expand...

"How Can I Tell What Ignition System Is Fitted On My Bike?
Look for the colour of the ignition unit and what type of coils you are running:

MKIII and MKIV - ignition boxes are black and run with the original coils or similar replacements

Micro Digital - ignition boxes are red (old style Micro Power ignitions were also red) and run with the original coils or similar replacements

Micro Power - ignition boxes are blue (old style Micro Power ignitions were red) and run with miniature specialist coils

ID units - positive units are red, negative units are black (these systems both have LED's positioned at the top of the unit)"

To add to Les's input:

Micro MarkIII Ignition is the analogue system that most people that have a Boyer will have.
It likes 12 volts from the battery - less will give you starting problems, stuttering running, and kickback.

This was replaced by the Micro MarkIV Ignition a few years ago.
The look exactly the same - same stator plate, and same black box.
These will work down to 8 volts, and they have changed the ignition curve at very low RPMs making it easier to start.



The Micro Digital (red box) and Micro Power (blue box) systems are both digital, and both contain circuitry that will stabilise idling among other things.

• Boyer Bransden are insistent that suppressed plugs or caps are used on both these systems.

• It is important to note that the Micro Power (blue box) systems will not work with standard Lucas 17M6 (LU47275) or equivalent coils - you must use their COIL00008 unit instead.

L.A.B. said:

Boyer Bransden Electronics Ltd

"How Can I Tell What Ignition System Is Fitted On My Bike?
Look for the colour of the ignition unit and what type of coils you are running:

MKIII and MKIV - ignition boxes are black and run with the original coils or similar replacements

Micro Digital - ignition boxes are red (old style Micro Power ignitions were also red) and run with the original coils or similar replacements

Micro Power - ignition boxes are blue (old style Micro Power ignitions were red) and run with miniature specialist coils

ID units - positive units are red, negative units are black (these systems both have LED's positioned at the top of the unit)"

Boyer Bransden Electronics Ltd

Click to expand...

Thanks L.A.B. , maybe I was unclear but what I meant was the operational differences. (or features) I.E. idle stabiliization, low battery starting etc. between the three types. They don't seem to have a comparison (that I can see).

From my 1989 article: http://atlanticgreen.com/boyerexposed.htm

Boyer Exposed
By David Comeau October 1989


My first Commando, bought new in July, 1970, was an unmitigated disaster. In September, 1987 I bought my second Norton Commando, a '72 Combat, and to insure some useful life for this motorcycle, I have been studying everything I can get my hands on. I've learned quite a lot in nineteen years, part of which is patience and skepticism, and part of which is the subject matter for this writing, that being ignition characteristics, primarily those of the Boyer.

The general consensus is that the factory Lucas centrifugal advance points system is bad, and the Boyer / Lucas Rita systems are absolutely great. I want to know why, for both cases, but I will sometimes refuse to accept "parroted" endorsements due to lack of factual substance. An example of this is the lack of any advance curve specifications for both the Rita or Boyer.

I understand that early 750 Commandos, Combats and low compression 850's with a Boyer installed will run down the road under their own power. I also accept the contention that the Boyer is likely the best 'consumer' product as of this writing. However, having had a substantial amount of ignition curve tuning experience to know of the power and drive ability improvements that can be made with proper attention to detail, and what a pig a motor can be in the timing is too retarded, simple agreement with the concept that one advance curve fits all is too much 'Black Magic' from the 'Black Box' for me to accept.

gtiller said:

To add to Les's input:

Micro MarkIII Ignition is the analogue system that most people that have a Boyer will have.
It likes 12 volts from the battery - less will give you starting problems, stuttering running, and kickback.

This was replaced by the Micro MarkIV Ignition a few years ago.
The look exactly the same - same stator plate, and same black box.
These will work down to 8 volts, and they have changed the ignition curve at very low RPMs making it easier to start.



The Micro Digital (red box) and Micro Power (blue box) systems are both digital, and both contain circuitry that will stabilise idling among other things.

• Boyer Bransden are insistent that suppressed plugs or caps are used on both these systems.

• It is important to note that the Micro Power (blue box) systems will not work with standard Lucas 17M6 (LU47275) or equivalent coils - you must use their COIL00008 unit instead.

Click to expand...

Aha, that's what I meant, thanks for that.

Just replaced the Boyer (year old mk4) on mine with a Tri-Spark. It now ticks over at less than 1,200-1,300 revs. Feels a little sharper through mid range, maybe a little flatter top end (4,000+). All that based on setting at 30° at full advance.

Main improvement is it's so nice to actually trust it will tickover and run well at bottom end I could never get it to do so with the Boyer, despite fiddling with timing, air screws, float heights, blah blah.

gtiller said:

Micro MarkIII Ignition is the analogue system that most people that have a Boyer will have.
It likes 12 volts from the battery - less will give you starting problems, stuttering running, and kickback.

Click to expand...

In 2001 I was asked to update my original research article, which I did,
This is when I discovered the spark scatter effect which can be deadly to a MKIII electric start commando.
My article and research was leaked by John Healy to Ernie Bransden.

Now the whole world forgets the source of this information. It was my research and article.

On a trip to England, I met with Enie Bransden and the engineer (who left to start PAZON)
and my research was acknowledged and confirmed by them....

So far you are only being told the "marketing garbage" about the products.
I can tell you what the actual technical characteristic differences are. The problem is few (very few) people will understand.

dynodave said:

So far you are only being told the "marketing garbage" about the products.
I can tell you what the actual technical characteristic differences are. The problem is few (very few) people will understand.

Click to expand...

All info gratefully received here Dave.

Duty cycle, advance curve, and voltage sensitivity are each of interest and the basic characteristics that affect the operation and many talk about without the technical basis.
First and simplest is the different duty cycle characteristics which in baby talk translates into the coils used...WHY???

The duty cycle characteristic is called DWELL. percentage of time the coil is being driven with voltage
The Rita dwell is an exceptionally long dwell 98%. full accounts for the high AVERAGE current draw.

The analog Boyer MK3-black box dwell at low rpm is around 87% and by 6000 rpm the dwell goes down to 78%. Going down is not the actual engineered desired output. With the same coils the Boyer is less hungry for powerthan the rita.
This compares with points/coil that each runs about 45% duty cycle but is still characterized as LONG dwell.
The Boyer MICRO DIGITAL is not analog but is still LONG DWELL duty cycle

The boyer MICRO POWER is also not analog but microprocessor controlled and is a SHORT DWELL system, Terms like high power are sometimes used but not alwaysunderstood. The dwell is typically in the 17-20% of the time will be On and driving different characteristic coil that are matched to the electronic components.
All this duty cycle talk is actually focused on controlling the heat generated in the output transistor.

Normally a transisitor is rated on it's ability to resist damage from heat. It does this by matching the maximum time on with the amount of current. The system voltage is considered to be a controlled and fixed 14.3V.
A long dwell system has lower current for a longer time and should not over heat the output transisitor. The low current is in direct response to the higher resistance coil.
HEAT is the final killer of the output transistors.

The short dwell system has much higher surge current but for a much shorter time and the AVERAGE heat of the output transistor is still within the heat tolerance level.
Strange as it may seem, but the output transistor part number and type can be the same for both long and short dwell.
The AVERAGE heat is the same for both systems but the time(% dwell) and current level are different.

The ignitions systems relate very much with my radar career where a ,0025% duty cycle and thousands of peak current would make a whimpy 250,000 watts of peak power and I have worked once(only once) on 6 million watt peak power. It was dangerous as it also made X rays in the cabinet. 60,000volts will kill you if the xray does not.
These motorcycle ignitions are about 40 watts, I consider them as toys...

In the late '70s I used to repair the Rita boxes using a TV line switching power transistor! BU207 I think, but that is a long time ago.

SteveA said:

In the late '70s I used to repair the Rita boxes using a TV line switching power transistor! BU207 I think, but that is a long time ago.

Click to expand...

Sure you were a hero too-but not a magician!

Sure a few hundred volt rated (unprotected) darlington transistor can work. I have done it myself. However unless you have the later added zener stack in parallel (like the boyer) the transistor can go bad if the coil wire fall off and the output transistor gets slamed with high voltage reflected spikes(burn). The out put transistor can eventually die as the boundry has become compromised and it is like thermo nuclear run away...

The final version of both the boyer and rita version had a later transistor updated design with an internal circuit that provided some degree of protection. That is when the AB11 rita went from the single varistor"A' version to the "B" version with the new internal regulator transistor. When that final TO-3 transistor went obsolete it caused the end of the rita production. This was related to me in person by John Carpenter.

ADVANCE CURVES

I taught jr. college level for 7 years while in the USAF and the thought of trying to teach advance curve principles is quite depressing.
The 28 vs 31 degrees at 5000 discussion on this forum lets me know it is almost hopeless. Sorry I will not be typing a 3 semester hour college course.

Advance curve is the result of the process of correctly igniting the fuel air charge, which varies in pressure based on the throttle setting.
How the advance curve, if any exists, to compensate for the pre igniting of the fuel/air by a predetermined time to compensate for the quicker rotational period.
It is a time vs rotational speed, degrees/second, calculation process to control a spark generating device/subsystem .
Secondary more complicated systems, routine in cars, based on the amount of throttle will modify the ignition timing due to the change of combustion event duration.
The variable preignition physical position when properly done provides the best integrated/"average" pressure pulse push on the piston.

dynodave said:

Sure you were a hero too-but not a magician!

Click to expand...

Now what did I do to deserve that?

I claimed no heroics nor magical skills. The ignition went bad and I went to work and serched around with a colleague for something we might have in our stores that might fix my Rita. He fixed TVs as a paying sideline/hobby and said let's give this a go. That is what we did!

They were in stock as listed parts for the flight simulator visual display system fitted to the Phantom simulator we supported.

And for an impoverished young racer....free! Kept me racing for the rest of the season, and the next if I recall.

Was it a fragile solution? Yes, I did it more than once, but thankfully the following occasions were not whilst on track!

For what it is worth (not much), I was talking to Mrs Les Emery at Cadwell Park after I had done it first time, and she was rude to me too!

At the time I assumed it was because they were doing the same...for reward!

dynodave said:

ADVANCE CURVES

I taught jr. college level for 7 years while in the USAF and the thought of trying to teach advance curve principles is quite depressing.
The 28 vs 31 degrees at 5000 discussion on this forum lets me know it is almost hopeless. Sorry I will not be typing a 3 semester hour college course.

Advance curve is the result of the process of correctly igniting the fuel air charge, which varies in pressure based on the throttle setting.
How the advance curve, if any exists, to compensate for the pre igniting of the fuel/air by a predetermined time to compensate for the quicker rotational period.
It is a time vs rotational speed, degrees/second, calculation process to control a spark generating device/subsystem .
Secondary more complicated systems, routine in cars, based on the amount of throttle will modify the ignition timing due to the change of combustion event duration.
The variable preignition physical position when properly done provides the best integrated/"average" pressure pulse push on the piston.

Click to expand...

My Rita, supplied to me by Tony Smith, complete with Thruxton sourced cut away timing cover and pick up, had an interesting solution for the advance curve, it was simply jumpered out!

PS, I was serving with the Royal Air Force at the time!