BritBike Forum logo
BritBike SponsorBritBike SponsorBritBike SponsorBritBike SponsorBritBike Sponsor SteadfastCyclesBritBike SponsorBritBike SponsorBritBike SponsorBritBike SponsorHepolite PistonsBritBike SponsorBritBike Sponsor
Upgrade to: Gold Membership | Premium Membership | Vendor Membership | Site Sponsor Membership
Member Spotlight
htown
htown
Magnolia, TX
Posts: 1,551
Joined: March 2006
ShoutChat Box
Comment Guidelines: Do post respectful and insightful comments. Don't flame, hate, spam.
Search eBay for motorcycle parts in following countries
Australia, Canada, France, Holland, Italy, United Kingdom, USA
Random Gallery photo
a word from..
Manuals on DVD (Shipping included)
Previous Thread
Next Thread
Print Thread
Rate Thread
Spark plug gap with boyers
#133468 01/23/08 4:38 am
Joined: Sep 2006
Posts: 731
BritBike Forum member
OP Offline
BritBike Forum member
Joined: Sep 2006
Posts: 731
'71 TR6 650, stock bike.
when running a boyers ignition, should the spark plug gap change from the original spec(0.25")?

Support Your #1 BritBike Forum!

Check out British motorcycles for sale: British Motorcycles on e-Bay UK, British motorcycles on e-Bay North America
Re: Spark plug gap with boyers
#133469 01/23/08 4:45 am
Joined: Feb 2004
Posts: 1,945
BritBike Forum member
Offline
BritBike Forum member
Joined: Feb 2004
Posts: 1,945
It comes down to what the coils will take. I run .040 gap using an Accell and or a Dyna duel output single coil. Very much snapper response, better idle, better top end,better MPG. It also makes it easer to run leaner mixtures "more power".


norbsa
1960 TR6
1963 Super Rocket
1965 650 Star
1966 441
1968 Thunderbolt
1969 Twinkle 250
1972 Fastback
1974 Roadster
1970 S.S
Way too many BSA's not named
http://decentcycles.com
Re: Spark plug gap with boyers
#133470 01/23/08 3:26 pm
Joined: Sep 2006
Posts: 731
BritBike Forum member
OP Offline
BritBike Forum member
Joined: Sep 2006
Posts: 731
I'm running a pair of the 6V Lucas look-a-like coils and have been using .30-.32. I'll try opening it up a bit more and watch for changes. I have an accell twin lead coil i was using, but didn't like how i had to mount it and when i found a real good price on a pair of the german Lucas style ones i swapped.
thks

Re: Spark plug gap with boyers
#133471 01/23/08 4:26 pm
Joined: Nov 2005
Posts: 7,606
Likes: 4
Born To Run
Offline
Born To Run
Joined: Nov 2005
Posts: 7,606
Likes: 4
I run the 6V look alikes with the stock gap on the N3's........runs like a champ.....

Steve


'77 T140J
"Vintage Bike". What's in your garage?

"The paying customer is always right."

Fitting round pegs into square holes since 1961...
Re: Spark plug gap with boyers
#133472 01/23/08 5:20 pm
Joined: Jun 2002
Posts: 10,045
BritBike Forum member
Offline
BritBike Forum member
Joined: Jun 2002
Posts: 10,045
Hi,

Quote
Originally posted by Terry_tr6:
boyers ignition,
should the spark plug gap change from the original spec(0.25")?
No.

Quote
Originally posted by Terry_tr6:
.30-.32. I'll try opening it up a bit more and watch for changes.
At best, you'll simply end up with a misfire.

At worst you run the risk of buggering the electronics. When the spark fails to jump too-wide a plug gap, it's still searching for a path to earth/ground. Electricity will take the easiest path to earth/ground; if that happens to be through the transistor box (and, yes, it does happen, more frequently than you'd like and generally to people faffing about with the bike's plug gap(s) wink ) ... well, what do you imagine happens to components designed for millivolts or a few volts when you push a few thousand volts through 'em? eek

Hth.

Regards,

Edit: so the 'naughty words filter' doesn't allow 'a-n-a-lysis' but does allow 'bugger' :rolleyes: - Morgan, I'd ask for your money back. wink

Re: Spark plug gap with boyers
#133473 01/23/08 5:25 pm
Joined: Aug 2007
Posts: 4,493
BritBike Forum member
Offline
BritBike Forum member
Joined: Aug 2007
Posts: 4,493
Stuart is right, you are testing the dielectric strength of all the HT components. Hopefully the HT will just track through your HT leads or caps and not damage your coils.

HTH

Blapper redwine

Re: Spark plug gap with boyers
#133474 01/23/08 5:49 pm
Joined: Feb 2004
Posts: 1,945
BritBike Forum member
Offline
BritBike Forum member
Joined: Feb 2004
Posts: 1,945
Quote
and, yes, it does happen, more frequently than you'd like and generally to people faffing about with the bike's plug gap(s) [Wink] ) ... well, what do you imagine happens to components designed for millivolts or a few volts when you push a few thousand volts through 'em?
Oh please let me hide me head in the sand a little longer... It's only been about ten years running bikes with .040 gaps. No component failures yet. I am not the person inventing the change just happily using it. If I couldn't use the bigger gaps I just go back to points. JMO


norbsa
1960 TR6
1963 Super Rocket
1965 650 Star
1966 441
1968 Thunderbolt
1969 Twinkle 250
1972 Fastback
1974 Roadster
1970 S.S
Way too many BSA's not named
http://decentcycles.com
Re: Spark plug gap with boyers
#133475 01/23/08 6:33 pm
Joined: Jun 2002
Posts: 10,045
BritBike Forum member
Offline
BritBike Forum member
Joined: Jun 2002
Posts: 10,045
Hi,

Quote
Originally posted by norbsa48503:
Oh please let me hide me head in the sand a little longer...
Information and view of big box of buggered transistor boxes courtesy the tech. guys at Bransden Electronics.

Hth.

Regards,

Re: Spark plug gap with boyers
#133476 01/23/08 9:53 pm
Joined: Sep 2006
Posts: 731
BritBike Forum member
OP Offline
BritBike Forum member
Joined: Sep 2006
Posts: 731
Thanks stuart. Didn't consider that too much gap might have an effect like sneezing with a mouth full of diet coke....
For educational sake, anyone know what the determining factor is on what spark gap gets specified? I'd think it is related to the coil output voltage. Of course that is probably influenced by the current and waveform of what gets input to the coils from the points or black box.. So i'd think Boyer would be the people to best say what gap to use with a peticular coil on thei system.

Re: Spark plug gap with boyers
#133477 01/23/08 11:40 pm
Joined: Aug 2001
Posts: 1,861
BritBike Forum member
Offline
BritBike Forum member
Joined: Aug 2001
Posts: 1,861
Terry ... we need more info regards your question on plug gaps using a Boyer ignition. The Boyer [email protected] and Micro Digital are 'dwell' type systems that merely replace the points and advance pieces with electrical switching of the battery voltage to the coil. The primary of the coil will never see more than a 12v input. So ... the output voltage to the plugs will be determined by the coil design, the same as supplied with a points ignition.
However the Boyer Micro Power ignition using the dedicated 'pulse' coils will supply a much higher voltage allowing wider plug gaps for improved engine performance. BTW these are the same coils as used on the Hinkley Triumph. hmmmm.

Wide plug gaps are a 'good thing' for improved power and efficency in any/all engines. This is of particular importance with lean fuel mixtures for best mileage.
But the advantage for us is to allow good combustion of our often times marginal correct mixture with our ummm ... crude carbs on our olde BI high performance engines.

You don't suppose Every manufacturer of All engines in the last 20-30 years use a more expensive high performance electronic ignition just 'for fun' do you? No.. These ignitions allow a wider spark plug gap and of course more precise timing.

I believe you will find the limitations of an excessively wide plug gap will be possible coil damage due to internal arc over in the HV windings and of course miss fires due to inadequate coil voltage. All coils are Not created equal!
I find it 'a stretch' that a excessive wide plug gap could possibly cause any damage to the ignition 'box'. hmmm

A 'pulse' type ignition such as the Boyer Micro Power, allows 35-40 thou plug gap even in a 11-12:1 compresh engine. These are a huge improvement over the older 'dwell' type ignition systems. These modern ignitions also have the advantage of delivering nearly full voltage to the plug vs the slow 'ramp up' of the HV applied to the plug, for improved firing under less than optimum conditions.

I'm anxious to hear more about the digital Pazon ignitions. They sure 'read good'. BTW, I've signed up for the Pazon newsletter. The first chapter I recieived explained and compared the trigger systems of the Boyer and Pazon.

I notice Pazon uses a 'Hall Effect' trigger in some models which is surely a big improvement on the basic magnetic trigger supplied by Boyer.
However the 'Crank Triggered' Boyer Micro Power as we and many others use on race engines, also uses a modern type 'reluctor' trigger pick up. I'm anxious to adapt one to a road bike engine. hmmm ..


Dave - NV
Re: Spark plug gap with boyers
#133478 01/24/08 12:17 am
Joined: Apr 2006
Posts: 1,704
BritBike Forum member
Offline
BritBike Forum member
Joined: Apr 2006
Posts: 1,704
What dave-NV said.
Excellent post.


Stop the insanity.
Re: Spark plug gap with boyers
#133479 01/24/08 12:17 am
Joined: Aug 2001
Posts: 3,896
In Remembrance
Offline
In Remembrance
Joined: Aug 2001
Posts: 3,896
Great stuff from you Dave - as always :bigt:

beerchug

Re: Spark plug gap with boyers
#133480 01/24/08 12:59 am
Joined: Aug 2005
Posts: 1,714
Likes: 1
BritBike Forum member
Offline
BritBike Forum member
Joined: Aug 2005
Posts: 1,714
Likes: 1
air fuel mixture also involved: leaner harder to fire, big kv coils more gap.most of our Boyer fired are on .030 to .040 gaps.our twins run dual tower single 3 ohm coils.plug gap .040. 3 triples one Lucas fired rita & one Boyer fired still on the original 6v coils. the t150 Boyer on jap 6v coils
all the triples on .030 plug gap.all have copper core plug wires and non resistor plug caps.plugs are anything non resistor n4 n7yc bp6&7's florida gas is junk we stick with high test major brand.the reed vapor pressure is low so the mixtures are a little fat to help starting and low speed running. this is what works for our older brit bikes. my wifes 01 bonny has over 12,000 miles on denso iridium plugs.the were free to try and i have pulled them out once looked and stuck um back in.apples and oranges.boils down sorting through different combos to see what works best for each different bike.

Re: Spark plug gap with boyers
#133481 01/24/08 1:37 am
Joined: Feb 2004
Posts: 1,945
BritBike Forum member
Offline
BritBike Forum member
Joined: Feb 2004
Posts: 1,945
This goes back to 1995 I was using Bosch Platinum WRP 7's with standard Boyer copper wires when I closed the gap they didn't work well so I put them in how they came .040. At that time it was a 650 BSA. Harley gray single coil.
In 1999 I am on a 750 Norton I see CNW guys there at the rally they are running Autolite Platinum AP63's .040 gap. So there is some history of this working. I use the AP64's now in the 750 Commando Don't know if I would try that in a Triumph though. I have run this Norton 250 miles at 80 MPH several times. I am in Michigan(self defense speed). Please don't tell me I can't do that anymore. Now the coil is in the wind and so is the Boyer box right under the tank.The plug wires are very short Have to run non resistor NGK caps nothing else will stay on.


norbsa
1960 TR6
1963 Super Rocket
1965 650 Star
1966 441
1968 Thunderbolt
1969 Twinkle 250
1972 Fastback
1974 Roadster
1970 S.S
Way too many BSA's not named
http://decentcycles.com
Re: Spark plug gap with boyers
#133482 01/24/08 2:58 am
Joined: Sep 2006
Posts: 731
BritBike Forum member
OP Offline
BritBike Forum member
Joined: Sep 2006
Posts: 731
Digesting....
Need more antacid tablets.
Running fine with .32 gap guess i'll stay pretty close to that unless i go back to the HO coil

Re: Spark plug gap with boyers
#133483 01/24/08 9:11 am
Joined: Aug 2007
Posts: 4,493
BritBike Forum member
Offline
BritBike Forum member
Joined: Aug 2007
Posts: 4,493
Like I said up top, the threat is most likely the leads and caps tracking.

With Norbsa's long term experience at 0.040", 0.032" looks like the smallest risk imagineable. I am going to check the gaps out when I finish my build. IME if the caps, leads or coils do struggle you can close up the gaps to get you home without a problem, so it's a low risk as they go.

Blapper redwine

Re: Spark plug gap with boyers
#133484 01/24/08 12:59 pm
Joined: Aug 2001
Posts: 1,351
Crew Chief
Offline
Crew Chief
Joined: Aug 2001
Posts: 1,351
Dave-NV
"I find it 'a stretch' that a excessive wide plug gap could possibly cause any damage to the ignition 'box'. hmmm"

Hi Dave
small gap=small inductive reflection to box

big gap=bigger inductive reflection to box

Failure to fire across bigger gap= even bigger inductive reflection to box
Pull the wire off the plug and you have a high risk of box failure due to "punching holes" in the semiconductor material. Immediate failure is not common but eventual failure is a fairly sure bet o older systems. I have seen it all time and time again.
The output transistor protection schemes have changed over the years and have improved and therefore will just take more abuse before failure is induced.


dynodave
BSA 3 1961-1963
Ducati 3 1992-2002
Norton many 1951-1975
87 Serv-Equip 100HP MC brake dynamometer,
Re: Spark plug gap with boyers
#133485 01/24/08 2:48 pm
Joined: Feb 2004
Posts: 1,945
BritBike Forum member
Offline
BritBike Forum member
Joined: Feb 2004
Posts: 1,945
Thanks for that Dave, So all of us using larger plug gaps are pushing it for sure. I am not willing to go back so I will write back when mine fries.Hoping for another ten years.LOL Until I started using the NGK non resistor caps I was having problems with the others popping off on the road.Commandos shake a bit. I wonder how many fried ones are a result of this as opposed to too much gap.


norbsa
1960 TR6
1963 Super Rocket
1965 650 Star
1966 441
1968 Thunderbolt
1969 Twinkle 250
1972 Fastback
1974 Roadster
1970 S.S
Way too many BSA's not named
http://decentcycles.com
Re: Spark plug gap with boyers
#133486 01/27/08 2:40 am
Joined: Jun 2007
Posts: 150
BritBike Forum
Offline
BritBike Forum
Joined: Jun 2007
Posts: 150
I read the above with amusement. 6CA points for 90K miles. No problems, rarely adjusted, changed twice, and it wasn't necessary. NGK B7ES at .028" and Taiwan replacement Lucas type coils......cost for two was 22 dollars. Taylor spriropro wires.


What, me worry?

Moderated by  John Healy 

Link Copied to Clipboard
Home | Sponsors | Newsletter | Regalia | Calendar | Bike Project | BritBike Museum | Spiders Cartoons | DVD- Manuals & Parts books
Upgrade to: Gold Membership | Premium Membership | Vendor Membership | Site Sponsor Membership
Powered by UBB.threads™ PHP Forum Software 7.7.4