19.1 Electrical Ignition Balast Resistors.

From: Jim Piercy
Date: Mon, 10 Apr 1995 22:02:35 -0300

Erv Says:

> I have never quite understood the logic of the 6V coils. What
> do people think of switching to 12V throughout - have people
> done it, and if so with what success (or not..). I'm also
> toying with a switch to the Boyers. Do they make a 12V system
> as well?

You have to understand the concept of "nominal" voltage ratings. Norton used a "ballast resistor" to limit the primary voltage appearing across the 6 volt coils to something more than 6 volts but something less than 12 volts with the result that they pulled a higher current and thus a higher intensity spark off the secondary of the coil than would be possible on a 6 volt system. Make no mistake though, the entire system is already operating at 12 volts.

If you were to eliminate the ballast resistor and go for 12 volt coils, you probably wouldn't help things much in the sparking department.

This is yet another example of there being at least three ways to do anything- the right way, the wrong way, and the British way.:)

Cheers,
Jim Piercy

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19.2 Boyer Installation.

From: D.J. Walker
Date: Thu, 10 Aug 1995 13:48:30 +0100 (BST)

Dear Russell,
Firstly, I suggest you obtain a copy of the fitting instructions for the Boyer system - you're sure to need them, again, especially when rewiring the ignition coils after having dismantlement, etc. Boyer themselves are very good about this, and will send free copies to you through the post (in the UK, at least). Alternatively, go to your nearest Boyer stockist and ask them politely for a photocopy of the A4 sheet from inside one of their boxes (be sure and get the instructions for the older Transistor Assisted Contact type, rather than Boyer's new microprocessor jobie!)

Here's how to realign the stator and rotor.

1) open the screw-in inspection cover on the primary case, so that you can see the timing quadrant and alternator rotor.

2) Remove the sparking plugs from the head, so's you're not fighting the engine's compression. Turn the engine over until you find the timing mark on the end face of the alternator rotor. (Make sure there's only one such mark on the alternator rotor. 1972/73 Commies had two marks, yours isn't such a bike, but it's worth remembering that all 74mm Lucas rotor will fit, so best to make sure - DPOs being what they are...

3) Align the timing mark with 31 degrees Before Top Dead Centre position indicated by the timing quadrant inside the inspection hole.

4) Put the signal-generator-rotor (the bit you took out assuming there'd be a Woodruff key on it) into the signal-generator housing such that the two magnets are in line with the big "Norton" logo on the timing case, i.e. they want to be dead horizontal, assuming your bike is sitting on a flat, level surface...

5) Fasten the rotor in place using the long long bolt, making sure nought's disturbed whilst doing this.

6) The signal-generator-statorplate now goes on with the wire terminals at the bottom. The two signal-pickup coilpacks should now be roughly lie at the half one/half seven (clockface) position. Notice that there are two holes just in from the inner rim of the centre of the stator. Line the one which is now roughly at 9o'clock (the other is somewhere around 7o'clockish) - line the 9o'clocker up with the magnet of the s-g rotor sothat you can see the magnet through the hole.... like this:

                "Norton" logo                                        Signal Gen.
                /                                  ____________      Stator plate
               /                                  /           c\      /
       N N  Nnnnnn    t     nnnnnn               /    _____  CCc\    /
     NN N N N     nnnntnnnnn      nn            |    /     \  C  |  /
        N N N  oo  rr t  oo  n nn    n          |   |       |    |
        N  NN o  o r  t o  o  n  n   n          |(X)|X <+> X|XX  |
        N   N  oo  r  t  oo   n  nn  n          |   |       |    |
                                     n          |  C \_____/     |
           nnnnnnnnnnnnnnnnnnnnnnnnnn            \cCC  WW       /
                                                  \_c__________/

Okay? The "C"s in this picture are the signal detector coils on the stator. The "<+>" bit is my attempt at the bolt in the centre of the rotor. The "WW"s are the wire connectors. The "X"s are the magnets of the signal-generator rotor, and the "(X)" bit is the hole in the stator with the magnet visible through it. (One day they'll make an e-mail system you can draw proper pictures on - Godelpuz, we might even be able to use *italics*!)

7) The stator fastening bolts should now be central in their slots.

Like I say, You'll need the singal sheet of instructions from Boyer, but in the means, this ought to get your bike running, so's you can start strobe timing it properly.

Commando Dan
Leicester, England.

Any questions - just mail me direct, and I'll try to help. Don't worry about the "stupid stupid stupid" bit - I did exactly the same thing first time out!

"An expert, is a person who has made all the mistakes possible in one very small area of expertise" Niels Bohr, a chap who knew a thing or two!

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19.3 Coil Interchangeability

From: Chuck Stringer
Date: Wed, 17 Aug 1994 13:17:39 -0500 (EST)

Actually, what I wanted to know is if coils are pretty much interchangeable. Can I use Kmart or VW auto coils on the BSA or should I be comparing resistance with the original Lucas coils? Are parts parts?

Chuck

From: Chuck Kichline
Date: Wed, 17 Aug 94 14:01:32 CDT

> Actually, what I wanted to know is if coils are pretty much
> interchangeable. Can I use Kmart or VW auto coils on the BSA or should
> I be comparing resistance with the original Lucas coils? Are parts
> parts?

I don't think they really are all interchangeable, but my own experience is that I ran an "epoxy" aftermarket Ford coil on my Victor (using a capacitor battery eliminator) for a couple of years with no unusual effects (other than easy starting and general reliability). I believe I used the Ford condensor too.

Chuck Kichline
Rust never Sleeps.

From: Robert D. Burget
Date: Wed, 17 Aug 94 13:03:25 PDT

> Actually, what I wanted to know is if coils are pretty much
> interchangeable. Can I use Kmart or VW auto coils on the BSA or should
> I be comparing resistance with the original Lucas coils? Are parts
> parts?

The old Cycle magazine article said to use ballast resistors unless the coils were of the type that didn't need them.

Someone else (i think on this list) said to use a reduced dwell angle to avoid excess current load if the primary resistance is lower.

I think I would check resistance and try to match it up.

Bob Burget

From: Mike Taglieri
Date: Thu, 18 Aug 94 01:10:53 EDT

>Actually, what I wanted to know is if coils are pretty much
>interchangeable. Can I use Kmart or VW auto coils on the BSA or
>should I be comparing resistance with the original Lucas coils?
>Are parts parts?

I used to use two K Mart automobile coils on a Honda 350; very odd looking, but they gave a hell of a spark. If I ever did this again, I'd try to use the condenser recommended for the K mart coils, however, because the Honda condenser wasn't right, and the things ate points for lunch.

One must be careful if using a Boyer, however. In a letter reprinted in Norton News, Boyer said, "Our units are designed to run with almost any ignition coil or combination that does not allow more than 4 to 5 amps of current through the unit." However, they RECOMMENDED "coil or coils that have a total resistance of 4 ohms or more" [i.e., 3 amps through the unit].

I believe this lower amp limit is to protect the coils, which the Boyer can easily fry if the current gets too high. Boyer also notes that separate coils more easily dissipate the heat generated, so they recommend 2 coils for a twin, rather than one of those double-headed coils. Plus, they suggest that "some heat sinking is provided by the case or mounting, i.e., not totally plastic covered."

Since you'd wire your coils in series for the Boyer, the resistance of the coils must be 2 ohms each [for a twin], which is true of both VW coils and Lucas coils. If you don't have enough resistance, you can use a ballast resistor to increase it. Of course, late model Commandos use 6 volt coils -- I have no idea what BSA's use.

From: Espen Olsen
Date: Thu, 18 Aug 94 10:43:13 +0200

>> Actually, what I wanted to know is if coils are pretty much
>> interchangeable. Can I use Kmart or VW auto coils on the BSA or should
>> I be comparing resistance with the original Lucas coils? Are parts
>> parts?
>I don't think they really are all interchangeable, but my own experience
>is that I ran an "epoxy" aftermarket Ford coil on my Victor (using a capacitor
>battery eliminator) for a couple of years with no unusual effects (other
>than easy starting and general reliability).
>I believe I used the Ford condensor too.

When I did the 6V -> 12V conversion, I just left the old 6V coil in place...(I couldn't wait to go for a ride). It was an aftermarket Lucas item anyway. Result: Great spark, easy starting, no problems yet.

I believe these old oil-filled coils are good heat dissipators

Espen
LA6MGA/LA1K
DoD#7962
Disclaimer?? What disclaimer?

Date: Thu, 18 Aug 94 07:31:51 -0700
From: Godfrey DiGiorgi

There are several many different kinds of coils made for different purposes. On motorcycles, we usually see coils designed for compactness and fitment into relatively small spaces, with one coil per plug (or two plugs per coil on many inline fours). To keep them compact, they usually have fewer primary windings thus require more saturation time to build up the magnetic field necessary to generate a spark. Thus long dwell angles and modest current consumption are typical.

(Dont forget about ET and flywheel magneto coils also. These require relatively fast field saturation times since they only get one or two pulses of juice through a crank revolution.)

Automotive coils are typically setup to have a fast saturation time since one coil will be called upon to fire 4, 6 or 8 plugs via a distributor. Thus they have low dwell angle requirements and tend to use a lot of current. Installing one on a motorcycle without modifying the dwell of the point cam normally causes them to consume an inordinate amount of juice and run hot. It was a good practice to do this in the mid-'70s when motorcycle ignition systems were showing their age as limp wristed spark producers, unable to keep up with the increasing demands of higher combustion pressure motors and higher rpm. Done right, with a re-machined point cam and more robust wiring to the coil to handle the additional current load, and assuming the bike's alternator produced enough power to keep up with the demand, automotive coil solved many a carburetion problem. Most, however, were done wrong and left the poor motorcycle with a battery that was always going flat and wiring harness problems.

Automotive coils are typically also designed to operate on three different current voltages: 6V for what few 6V automobiles still exist, 9V and 12V. The key here is that starting reliability is paramount for automobiles. On a cold, icy morning, the current draw of many cars' starters will drop system voltage to 9V or so. So the coil is designed to run on 9V power and starting under adverse conditions is assured... when the engine is running and the system voltage is in the normal 12-15V charging range, the current supply to the coil is routed through a ballast resistor to drop it to the correct 9V range. Otherwise the coil would overheat eventually and burn out.

This kind of solution, given the typically weak electrical power available on bikes, is terrible, particularly on a kickstart motorcycle. You're just throwing valuable current away as heat for no reason. On a kick only moto, you have no need to worry about starting voltage drop.

Many of the 12V coils for automobiles simply incorporate the ballast resistor as an internal part of the coil design. Again, this works but is wasteful of current.

My solution was to go to electronic triggering (like the Lucas-Rita, Boyer and Dyna ignition systems for Ducatis, Nortons and Triumphs) and use high quality Bosch or Lucas coils in 6 or 12V specification. Many times you could buy a higher output than stock Lucas coil from the Lucas catalog than came equipped on a bike, and both the Bosch and Lucas coils were a bit more robust than the Marelli units on the older Italian bikes, allowing a slightly great plug gap and easier jetting. Doing this, I reduced ignition system maintenance requirements and conserved electrical power for lights and charging, yet still obtained better starting and engine power at high rpm.
-- <D> ----------------------------------------------------------
Godfrey DiGiorgi

From: Nixion
Date: Fri, 19 Aug 94 16:50:12 EDT

when I converted my 57 t-bird to 12v, i kept the 6v coil, but on the advice of my mechanical advisor, inserted a ballast resistor in the line. so far, so good.

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19.4 Coil Polarity.

From: Mike Taglieri
Date: Wed, 24 Aug 94 02:14:10 EDT

>If anyone knows the secret to this I would be eternally grateful:
>The coil terminals are marked + and - but which is which on
>our old fashioned positive ground machines? Or does it even
>matter, especially when they are wired in series?

As far as I know, (+) and (-) work the same whatever is ground. Therefore, the (+) terminal goes to the contact breakers, which [when closed] are ground. The (-) goes ultimately to the battery.

Using a Boyer, you wire the coils in series, so one (+) and one (-) are connected together. Then, the other (-) goes to ground, and the other (+)goes to the black wire to the Boyer.

Count your blessings; on some old coils, the poles are marked (1) and (15) rather than with polarities. I have not a clue . . .

Mike Taglieri
Raul -- '72 Commando Interstate

From: Ralph Merwin
Date: Wed, 24 Aug 94 02:14:10 EDT

MikeTnyc@aol.com writes:
> As far as I know, (+) and (-) work the same whatever is ground.
> Therefore, the (+) terminal goes to the contact breakers, which
> [when closed] are ground. the (-) goes ultimately to the battery.
[Snip]

Well, the Boyer diagram shows hooking the (+) terminal of the set to the ground on a Norton (positive ground) and a different connection for a negative ground bike, implying that the polarity needs to be observed. If polarity didn't matter I'd think that the coils wouldn't have polarity markings...

Ralph

From: Chuck Stringer
Date: Wed, 24 Aug 1994 12:07:35 -0500 (EST)

Richard Neill Dabney writes:
> They are polarity sensitive. If you hook one up backwards the spark
> will jump from the outside electrode to the center electrode. This
> is especially bad for platinum plugs.

Wouldn't this happen on all postive earth systems since the polarity of the plug itself is reversed?

Chuck

From: Michael Schippling
Date: Wed, 24 Aug 94 10:53:20 PDT

> From: MikeTnyc@aol.com
> >If anyone knows the secret to this I would be eternally grateful:
> >The coil terminals are marked + and - but which is which on
> >our old fashioned positive ground machines? Or does it even
> >matter, especially when they are wired in series?
>
> As far as I know, (+) and (-) work the same whatever is ground.
> Therefore, the (+) terminal goes to the contact breakers, which
> [when closed] are ground. the (-) goes ultimately to the battery.

Well....my quantified Murphy's law holds true again....
(If there are two ways to do something, there's a .75 probability that it will be done wrong.)

I got two diametrically opposed answers to the above question, both of them very cogently reasoned....guess some day I'll just have to schlep the scope out where the CO won't kill me so bad and try all the combinations.

Now another question for the motor guys:

My T140, with about 500 miles on a rebuilt engine, smokes on the right cylinder....but mostly after I cut the engine. When the engine has warmed up, smoke drifts out of the right silencer for a minute or so. When its running I can see a bit more smoke on the right than on the left (at night with car lights behind), and the plugs look pretty much identical....any thoughts?

(And no, I didn't do the rebuild, I bought it from someone of unknown skill who did it and then pooped on finishing the bike....so anything could be wrong...judging from the external workmanship I found).

thanks
MS

From: Richard Neill Dabney
Date: Wed, 24 Aug 1994 11:43:48 -0700

>Well, the Boyer diagram shows hooking the (+) terminal of the set to the
>ground on a Norton (positive ground) and a different connection for a
>negative ground bike, implying that the polarity needs to be observed.
>If polarity didn't matter I'd think that the coils wouldn't have polarity
>markings..

They are polarity sensitive. If you hook one up backwards the spark will jump from the outside electrode to the center electrode. This is especially bad for platinum plugs.

From: Richard Neill Dabney
Date: Wed, 24 Aug 1994 13:34:09 -0700

>Richard Neill Dabney writes:
>>
>> They are polarity sensitive. If you hook one up backwards the spark will
>> jump from the outside electrode to the center electrode. This is especially
>> bad for platinum plugs.
>>
>
>Wouldn't this happen on all postive earth systems since the polarity
>of the plug itself is reversed?

No, because the coil polarity ('+' is now ground) is also reversed in respect to a negative ground system. The electron flow through the coil is in the same direction as a negative ground system, negative to positive.

From: Michael Schippling
Date: Thu, 25 Aug 94 12:05:18 PDT

Alright, I appologize for starting the coil inanity thread, too.... And I promise to stop beating the horse, as soon as it stops quivering....

It looks like the best answer so far is that you want the _electron_ flow at the plug to jump FROM the center electrode TO the chassis. This would mean a Negative going pulse from the coil (ignoring the fact that we are talking about a damped ringing AC...).

So, if I remember some one of those rules of thumb from basic science, the center 'tap' of the coil will want to go....umm...uh...positive?

Now back to the intent of the original question... If the terminals are marked + and -, and we assume that they are marked in such a manner as to indicate who gets connected to what to produce that ole' negative going pulse, then it follows that all coils are marked the same, no matter which way is up on your
system's wiring.

This would mean that the + terminal indicates the center tap of the coil, and that this terminal is _always_ attached to be closest to the positive end of the system, this being the chassis in the case of our little friends.

Or did I get it all topsy turvey up there somewhere?

oh good christ, I'm really sorry....

MS

From: Ralph Merwin
Date: Thu, 25 Aug 94 14:15:11 PDT

Michael Schippling writes:
> It looks like the best answer so far is that you want the _electron_
> flow at the plug to jump FROM the center electrode TO the chassis.
> This would mean a Negative going pulse from the coil (ignoring
> the fact that we are talking about a damped ringing AC...).

Hmmm... Don't know about this, but it sounds reasonable.

> So, if I remember some one of those rules of thumb from basic science,
> the center 'tap' of the coil will want to go....umm...uh...positive?

Well, as I remember my basic electronics and transformer classes way back when, coils are just about like transformers which have a primary and a secondary winding. Coils are similar to 'step-up' transformers. You put 6 or 12 volts in and get out several times that. The way it works is that the primary winding is charged up when current flows creating a magnetic field that surrounds both windings. When you break the primary circuit (the points open) the magnetic field collapses which causes current to flow in the secondary. The secondary winding in a step-up transformer is much larger than the primary, hence the higher output voltage. There is no center tap in this transformer. The only uncertainty I have is where the 'other' end of the secondary winding goes - maybe the case of the coil?

Ralph

From: Latte' Jed
Date: Thu, 8 Sep 94 17:59 EDT

> Well, I seemed to have sparked (so to speak) a rather heated debate.
> Although I'm not a big fan of electronic ignition, I think that I may be
> able to come up with an excuse for it on my '72 Tiger.

It is true that if an electronic ignition craps out you're SOL (that stands for Sons Of Lucas, or Scions to be PC) and if you have points you can scrape something together with a street cleaner bristle and some screws salvaged from the battery box. I hate to inject some perhaps unwanted logic into a religious argument that deserves none, but with extremely few exceptions every single bike sold since the early 80's has had an electronic ignition, and we don't see masses of jap bike would-be riders huddled by the side of the road holding a street cleaner bristle wishing they had points. Someone recently asked something along the lines of what's wrong with fiddling with your points and valves? Nothing at all! If your revamped old britbike runs too good get another one! Make it a real junker, buy it in lots of boxes, and use the good bike to go annoy the old guy at the hardware store about the subtle differences between Whitworth and British Standard.

Seriously though, if the overbored tiger has starting problems an EE definately wouldn't hurt. Not sure if the Boyers or Ritas do this, but the black box on my Morini fires at something like 10 degrees ATDC below idle, so it genuinely cannot kick back, although next to a B50 (mine has a Boyer) a 175cc piston kicking back isn't that scary.

From: Mike Taglieri
Date: Fri, 26 Aug 94 01:21:02 EDT

>Now back to the intent of the original question . . .If the terminals
>are marked + and - . . . this would mean that the + terminal
>indicates the center tap of the coil, and that this terminal is
>_always_ attached to be closest to the positive end of the
>system, this being the chassis in the case of our little friends.
>Or did I get it all topsy turvey up there somewhere?

No, as far as I know that's exactly right. (+) is connected to ground. I think because MY original post had a typo, I'm the one responsible for getting at least some people screwed up. Sorry.

Mike Taglieri

From: Ralph Merwin
Date: Fri, 26 Aug 94 14:15:11 PDT

> The ignition coil is a transformer with one end each of the primary
> and secondary tied together:
>
>                 (center tap)
>   frame-------points-------|             spark
>                            |
>                            |                      -- * ---frame
>   battery-------           |                     |
>                 |__/\/\/\/---/\/\/\/\/\/\/\/\/\__|
>                   primary        secondary
>                 |<--------coil------------------>|

Your description is correct, but the drawing is a bit off. Here's my interpretation of what the schematic would be:

                                secondary
   plug-----------------   ----  ----  ----  ----  ----
                        |  |  |  |  |  |  |  |  |  |  | -------frame
       battery-------   |  |  |  |  |  |  |  |  |  |  | |
       (points)      |__|\/|/\|\/|/\|\/|/\|\/|/\|\/|__*_|
                     |  |  |primary |  |  |  |  |
                        |  |  |  |  |  |  |  |  |
                        ----  ----  ----  ----  ----

                    |<-----------coil----------------->|
 

Note there's no center tap. Just two coils with a common end. The drawing is, of course, *way* out of scale. The secondary is very large compared to the primary. You can locate the common end if you have a nice, sensitive ohm meter. Measuring from the plug wire lead to each of the (+) and (-) terminals will result in one measurment having a lower reading. This is the common end.

The common end should go to the frame to provide an adequate ground (and a strong spark), elsewise the energy of the spark is taken by the battery (via the points), which is probably not good for battery life...

Ralph

From: Peter Aslan
Date: Thu, 16 Mar 1995 12:56:44 +0000 (GMT)

> Hello all,
> This weekend, while reinstalling my ignition system on
> the Bonneville, I was preparing to hook up the coils
> to the wiring harness. At this point, while scanning
> the schematic, it showed a positive and negative connection
> to each coil, on the low voltage connectors. My coils have
> no indication on them to show a voltage bias. So, is there
> a check to be performed on the coil, to indicate what would
> be correct? Or does it matter?

Not sure if this has been covered or answered yet so here goes.

Yes it does matter which way round the coils LT, (Low Tension) connections go. Otherwise the spark jumps the wrong way across the plug gap and you may have problems with ignition system earthing.

If the LT Connections are not marked + and - Then it may be marked with CB and SW. SW is for Ignition SWitch, CB is for Contact Breaker and is the Negative terminal on a Positive Earth Bike, got that ?
 


Of course if its a Negative Earth Bike, it goes the other way round.

BTW, Coil Saddle Screw Torque is recommended for all coils except:

MA6, MA12, 17M6 and 17M12 Coils: 10-14lbf.in (1.13-1.58Nm)

MA6 and MA12 Coils: 5-10lbf.in (0.56-0.79Nm)

17M6 and 17M12 Coils: 8-12lbf.in (0.90-1.36Nm)


Sort of reverse Logic there, 'all coils except', this was taken form the Lucas manual and is I guess indicative of the Black art of Motorcycle Electrical work.

Too much torque and the coil will short out.

Peter Aslan (aka Captain Norton). Louden Quill Award.

From: Michael Schippling
Date: Fri, 17 Mar 95 10:35:16 PST

> From: Peter Aslan <paslan@uk.mdis.com>
> Not sure if this has been covered or answered yet so here goes.
>[Snip]

I thought this was beaten to a pulp here recently too....and the winner was:

Positive always goes to positive and negative to negative, no matter what the electrical system grounding scheme. The reasoning being that one wants a Negative going spark from the plug center electrode to the body and cylinder head. If the system is Positive ground it all makes simple sense, but if the system is Negative ground, then the spark needs to go MORE negative and since the coil acts as a transformer this is quite possible. As long as the coil polarity markings are adhered to the spark will 'jump' in the right direction.

In practice I'm not sure it makes much of a muchness, since I have had the same system wired both ways at various times and not noticed any performance difference. It may affect plug life though.

Someone on this list (I think) sent me a really luvly ASCII-DRAW(TM) of an ignition system that made it all make sense, but of course it has been lost in my BLACK-HOLE(TM) file system....

I have also been taken to task over my gas additive blurb yesterday.

Corrections:

1) The alcohol additives seem to be ethanol, not methanol.

2) Most additives are not alcohol but MTBE "methyl tert-butyl ether" or "methyl iso-butyl ether" CH3-O-C4H9

3) MTBE may not be hydroscopic, the jury is out still here.....call in the chemists.

But further comments are up for grabs:

1) [Additives] Actually burns hotter by adding more oxygen relative to fuel.

2) According to an article in Vintage Bike (TIOC news) the main reason for the contradiction (ie. a leaner mixture producing blackened plugs)is in addition to adding oxygenators they are also reducing the high volitility/low vapor pressure components is fuel. This results is a mixture which is difficult to atomize especially at low temperatures and leads to incomplete burning. Modern vehicles with closed loop feedback fuel injection can automatically compensate for the changes. Carburated vehicles like ours cannot. Supposedly as of January 1 another additive was to be included to minimze fouling.

1-- Nope...flame temperature is a result of the chemistry of the burning compound. Simple alcohols (and other short chain hydrocarbons) have fewer bonds to break per molocule and produce less heat when burned. You can actually light your hand on fire using 151 Rum and only lose a few hairs, but, kids, don't try this at home with gasoline...and don't run down the street trying to get away from the 151 flame like Richard Pryor.

2 -- Seems reasonable. But also produces lower flame temperature with more un-oxidized carbon to clutter up your combustion chamber.

As an extra bonus I found this uncontroversial chart in the BLACK-HOLE(TM) while looking for the coil diagram. It shows how to get a hotter plug. As we can see by inspection Champ plugs go up in number for hotter and NGK go down, just to keep us slightly off balance as usual:
 

Champion         NGK                 Bosch
Std type     Projected type
Cold
 N3           B-8ES  BP-8ES     W260T28,  W265P21
 N4           B-7EC* BP-7ES       -------------
 N5           B-6ES  BP-6ES     W200T27,  W200T30
Hotter
*= Competition Types (Shorter side electrode) Courtesy of NGK Spark Plugs

I'm really sorry. I'll never do this again.... If you believe me....send cash now.

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19.5 Lucas Coil Oil.

From: Mike Lake
Date: Tue, 10 May 94 09:52 EST

rcording@qntm.com says:
> Just got Clyde Earl's Vintage Videos Catalog. What an awesome
> selection of old race films and bike cult films (anyone else remember
> Robert Redford desert racing in "Little Fauss and Big Halsy"?).

> Clyde Earl / Vintage Videos
> 10619 Relton Avenue
> Inglewood, CA 90304
> 310-677-5865

If anyone's interested, I have an 8K list of motorcycle related movies I compiled a while back that I'll post. Just thought I'd check first due to the size.

> goes bad under extreme heat and loads. The coils are the Lucas
> originals, whose oil I topped off about 6 years ago when I put in
> the Boyer, but which otherwise have never needed service.

So, is this what the little straight-slotted screw thingies are in the top of my coils? Do I need to periodically check and fill the oil in the coils too? I guess I never gave it any thought because they don't leak... Anything british containing oil is supposed to leak, right?

(after riding my Bonny to and from work yesterday, it rewarded me by puking a big puddle of tranny oil on the garage floor last night. Looks like the big transmision sprocket seal...)

From: Stephen Hill
Date: Tue, 10 May 1994 13:45:00 -0700 (PDT)

Miketnc writes:
>The coils are the Lucas originals, whose oil I topped off
>about 6 years ago when I put in the Boyer, but which otherwise
>have never needed service."

I have never heard of servicing coils, or topping off the oil in coils. Where do you put the oil in? What kind? How do you know whey you need to do this? What if you don't? Does my curiousity show?

Stephen Hill.

From: Mike Taglieri
Date: Fri, 13 May 94 01:11:22 EDT

Sorry for the confusion. When I wrote: "The coils are the Lucas originals, whose oil I topped off about 6 years ago when I put in the Boyer, but which otherwise have never needed service," I didn't think anyone would bat an eye, but I seem to have caused a mini-frenzy. Yes, the "straight-slotted thingy" in the top of the coil is for oil, which apparently serves as an insulator/coolant. Yesterday I searched my literature looking for where I discovered that, but nothing is mentioned. Maybe I learned it by pouring some out -- who knows?.

Anyway, when I installed my Boyer in the mid-to-late '80's, I tried to rehab the whole ignition system. In the process, I filled each coil with Hoppe's #9 Lubricating Oil, a high-quality machine oil I happened to have dozens of cans of. Any good machine oil (e.g., sewing machine oil, clock oil, gun oil, etc.) would work, and probably light motor oil. I would not use 3-in-1 or other smelly oils, which are smelly because they vaporize. This is hardly a scheduled maintenance, since I've only done it once. Lucas probably put the screw there for its convenience in building the thing and had no intention that owners add oil during its life. On the other hand, they had no intention that people would still be using the coils 22 years later, as I am. Whether the oil "leaks out" I can't say. There's only a couple of ounces at most, so with most of our bikes it would scarcely be noticed, hmm?

To John Kula and Pete Serrino
rochester.edu: thanks for the tips on my spark-problem. I plan to check the system out and either move the Boyer box to a cooler spot, or put insulation between it and the engine. As for the coils, I was toying with replacing them with 6 volt Bosch coils for the VW beetle, which have a good reputation and a primary resistance of about 2 ohms, so the Boyer won't fry them. Also, they're small, as car coils go. Does anyone have recommendations on good coils to wire in series on a Boyer for Nortons (6 volt coils)? Then again, maybe the Lucas coils just need a fresh oil-change . . .

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19.6 Points

From: Peter Azlan
Date: Sat, 20 Aug 94 09:14:20 BST

There are two different types of contact breakers, (Points)around for the Commando, the difference is in the shape of the spring. The correct ones have a flat section, the incorrect ones have a more pronounced D shape or curve. They both come under the same Lucas number, the inferior ones, due to the shape of the spring cause the spring to fowl the mounting screws, which then causes the points to shortout and the engine to backfire, so beware.

Regards and happy riding, Peter Aslan, aka Captain Norton.

From: Steve Moseley
Date: Mon, 12 Sep 1994 23:00:41 -0700 (PDT)

My Commando 750 has points. I gap them, set the timing, and lubricate the auto-advance every 1,000 miles, and the bike idles and runs great. What am I doing wrong?

Steve

From: John S. Covell
Date: Tue, 13 Sep 1994 01:04:05 -0800

>My Commando 750 has points. I gap them, set the timing, and lubricate the
>auto-advance every 1,000 miles, and the bike idles and runs great. What
>am I doing wrong?

You're interrupting your riding every 1,000 miles to fart around with a point system.

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19.7 Sparkplug Equivalents

From: Jonathan Segel
Date: Fri, 10 Jun 1994 17:33:04 +0600

Asking again: can anybody post a brand-by-brand list of equivalents to Champion N3, N4 and N5?

I get the feeling some of my mail never gets there.....?

From: Nancy J Caputo
Date: Sun, 12 Jun 1994 21:39:39 -0700 (PDT)

>>asking again: can anybody post a brand-by-brand list of equivalents
>>to Champion N3, N4 and N5?
>>I get the feeling some of my mail never gets there.....?

Nope, your mail got here. Or there.

>From Shipman, Motorcycle Tuning for Performance:

Champion         NGK                 Bosch
Std type     Projected type
Cold
 N3           B-8ES  BP-8ES     W260T28,  W265P21
 N4           B-7EC* BP-7ES       -------------
 N5           B-6ES  BP-6ES     W200T27,  W200T30
Hotter
*= Competition Types (Shorter side electrode) Courtesy of NGK Spark Plugs

Lou TM LUIGI

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19.8 Sparkplugs.

From: Terry Drehmel
Date: Mon, 29 Aug 94 15:47:03 CDT

George K. asks if anyone has found a better plug than Champions:

No George, I haven't. I have found a blurb in the 1978 Triumph Service bulletin that more or less says:

"Don't use NGK plugs - they have a plating that can/will flake off into the combustion chamber."

From: Robin Tuluie
Date: Mon, 29 Aug 94 17:20:17 -0400

>George K. asks if anyone has found a better plug than Champions:
>"Don't use NGK plugs - they have a plating that can/will flake
>off into the combustion chamber."

I have used NGK B9EV plus for years in my race bike and BP7EV in my street bike without any problems at all. They last well, don't oil foul easily and I have noticed no power difference b/w Champion and these NGK plus in my race bike on the Dyno. I just have gotten some free plugs (sponsorship from Brian Capps) from Autolite and will try these next (Nelson ledges 9-3 and Summit point 10-9). Post me in a few weeks if you'd like to hear how they worked.

R.T.

P.S. I didn't like ND plugs, however. They seemed to oil foul easier and also have quality control problems.

From: George Kozak
Date: Mon, 29 Aug 94 15:14:09 PDT

I have a couple of questions:

Has anyone found a better plug for Triumphs than the original Champion N series?

Has anyone tried the Accel aftermarket MC coils with Triumphs?

Thanks in advance,
George

From: John S. Covell
Date: Tue, 30 Aug 1994 02:43:33 -0800

>I have a couple of questions:
>
>Has anyone found a better plug for Triumphs than the original Champion
>N series?

Can't say as to Triumphs, but for Norton I have long found the NGK BP7ES superior to Champion plugs in every way.

From: Jonathan Segel
Date: Tue, 30 Aug 1994 17:20:26 +0600

The weird thing is, when I bought my Triumph (T100SC) it had Autolite 403's in it. and ever since, even after total rebuild, it still runs those plugs better than the Champs, although I admit that it does have N4c's in it right now...

ps, i know it ain't brit, but i just finished putting together a '73 Duc 350 scrambler and am having a little trouble with it. i think the valve timing is off, even though everything lines up inside. anybody with experience here? and what kind of sparker do i use for this?

From: Pete Serrino
Date: Wed, 31 Aug 1994 08:59:19 -0500 (EST)

>>Can't say a to Triumphs, but for Norton I have long found
>>the NGK BP7ES superior to Champion plugs in every way.

I have run Champion N7YCs in my Norton for many years with few problems. In addition I have tried many other types to see if the Champions could be improved upon. I never found much difference in performance or gas mileage but I had heard a number of folks complain about Champions.

Last year I was making an adapter to enable me to pressurize the cylinders with compressed air (for valve stem checking, leak down tests, etc.). When I broke off the ceramic on a Champion plug I discovered the connection between the copper core and the top connector was only a slip on fit. It was not crimped or welded together effectively forming a second, albeit small, spark gap. Checking a few more Champions showed the same construction. I did the same thing to a Bosch plug (platinum) and found the center electrode to be firmly bonded.

Maybe this has something to do with Champions inconsistent performance.

Pete

From: Graeme Harrison
Date: Wed, 31 Aug 94 9:20:57 PDT

|had heard a number of folks complain about Champions.

The lower threaded insert on a Champion spark plug broke off from the rest of the body when I was removing it from the RH side of my '67 TR6R head many years ago. A little anti-seize brushed on the plugs might have avoided that problem. Last time I used Champions, too. No, the plug was not cross-threaded, just a POS. Had to remove the head and have the plug taken out by a local dealer.

WRT tyres, have always been an Avon RoadRunner fan FWIW. Never tried the Super Venoms as they seem to wear out faster than a bar of soap in the tub. :^)

From: Bob Cram
Date: Tue, 18 Oct 1994 10:44:52 +0000

The comments re changing your plugs made me think of something else. Try one heat range hotter. Variations of one heat range, even two sometimes, are usually not dangerous. If you are running too hot, you will know it right away because of detonation etc. and you can quit using those hotter plugs. Carry a couple of normal heat range plugs with you in case you have to make the change on the road. Plugs are cheap, so it's no big loss if it doesn't work. On the other hand, it may run beautifully, and you can do some plug readings after putting some miles on it to see if they are still fouling at all.

Manufacturers plug heat range recommendations are always based on the assumption of a certain type of riding. When our bikes were made they were some of the fastest bikes around, and the manufacturers may well have assumed they would be driven hard by 20 year olds, like sport bikes today. Guys like us don't drive them that hard (usually), so they may require a slightly hotter plug, just as you would go to a slightly colder plug for racing.

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19.9 Sparkplug Problems.

From: stephen
Date: Tue, 14 Jun 94 11:54:40 CDT

Pete writes:
> I have switched to Bosch Platinum (and resistor) plugs in my
>Norton (WR5DP) as platinum is supposed to fire better under adverse
>conditons (rich mixture, or oil fouling). They work fine even with my
>stock Lucas coils. I have also used Champion platinum (N3G) and NGK
>(BP7EV) with similar success. The latter two have a very fine tip which
>seem to burn down after about 12,000 miles though.

Have you actually run one of these plugs for that long? In a Norton?! If so I'm gonna go buy a bunch today. Are you running Amals? Or are you a carb adjustment wizard? I can never seem to get it *just right* (TM) so I'm always running a little bit rich (as I've seen with most other Nortons)so plug life is never that long.

p.s. This Fri, Sat and Sun at Blackhawk Farms in northern Illinois there's a combo vintage bike/auto/plane event. Motorcycle racing, Automobile racing and Bi-Planes doing stunts. Any brit-iron'ers planning on going? I'll post directions, etc. tomorrow or Thurs.

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19.10 Timing, (Dwell).

From: Gregg Kricorissian
Date: Thu, 11 May 95 11:36:43 EDT

Re: Bob's response to Chris' earlier posting:

>hmmm and I had always thought that the dwell was the time er
>duration the points were closed and allowed the coils to become
>saturated, electricly speaking

I laid back a bit at first, but I'm sure Bob is right: 'Dwell' relates to the time points stay closed (ie together), so that they conduct electricity, and 'Dwell Angle' is the related number of distributor cam degrees. As some may have already said, the dwell angle is important. This is because dwell sets the amount of time that current flows into the coils, and thus stores the energy which is then released to develop the spark (when the points come apart/disconnect). I wrote the following additional information to give some context, and improve the general understanding, (for what it's worth).

The energy storage issue raises an interesting point when comparing the relative merits of magnetos: In a normal points/coil ignition system, the spark energy is proportional to the length of time (dwell) that the points stay together. This is due to the inductance of the coil's primary, which limits the rate at which the coil's primary current can increase: (refer also to my earlier posting on "why you can damage a Boyer by leaving it turned on with the engine stopped"). As the engine revs increase, the points stay together relatively shorter and shorter periods of time. This means that less and less current flows into the coil, and less and less energy is stored there. Thus, less energy is available to then create a spark when the points open. Modern, 'high energy' ignition system get around this problem by employing a compact DC to DC inverter in the system which develops 300 to 400 volts to zap the coil primary with, instead of the puny 12 volts of the battery.

By contrast, the energy stored in a magneto increases as its rotational speed increases (different principles at work here, and I'll spare you the details). Consequently, the spark energy increases as engine speed increases, and this is one reason why many sports bikes were fitted with magnetos until the late 1960's. (It also explains why magnetos can destroy themselves with insulation breakdown when run constantly at high speeds). Magnetos eventually stopped being used because of their much higher cost, and the obvious superiority of points ignition in getting both cylinders timed accurately on a twin. (Yes, you should check both sides of your K2F twin mag: you may be surprised just how much different the timing is from one to the other.) In the heyday of magnetos, there were relatively few twins to worry about!

Hope this diatribe helps improve the general understanding of ignition systems.
...Gregg

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