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Discussion Starter · #1 ·
Hi,
done a bit of searching on here, but wanted to just confirm a few things. Please be liberal with corrections......

plug lead setup for boyer micro Mk3
- solid leads, NON resistor caps, resistor plugs (NGK br8 es) (my choice)
OR
- solid leads, resistor caps, NON resistor plugs (NGK b8 es)

Also how important is plug gap on these things? if so, is there a preferrred, non standard, setting for this ignition?

cheers
derek
 

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If you have resisted plug caps you can fit a multitude of non-resisted equivalent plugs.
A quick search result: B = 14mm thread. R = resisted type. 8 = heat rating. E = 3/4 thread depth. S = standard 2.5mm centre electrode.
The plug gap should be in workshop manual for your engine...usually .025" standard. Ditto the ignition timing.
The plug gap IS important.
I dont understand what you mean by non-standard setting.
If you mean the ignition timing, there`s only 3 settings, good, bad and indifferent.
 

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Incidentally, regarding the flame temperature number...champion numbers go up, but NGK go down, apparently.
e.g. cold..
N3--->B-8ES
N4--->B-7ES
N5--->B-6ES
hotter..
 

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This is my understanding please do not do this without more expert advise then mine. The reason the plug gaps were set at .028 was because the mag/ coil output would not support more. A gap of .035 will help give more complete combustion hence better idle and gas mileage. If you are using a high output coil ( 40,000 - 50,000) the wider gap should work better. I would like to here from people more enlightened them my self on this matter.
 

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I too would like some clarity from the experts on whether you should use any sort of resistor (plugs, wires or caps) with the Boyer Mk3. I'm still a little confused on this.
 

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Discussion Starter · #6 ·
The reason the plug gaps were set at .028 was because the mag/ coil output would not support more. A gap of .035 will help give more complete combustion hence better idle and gas mileage. If you are using a high output coil ( 40,000 - 50,000) the wider gap should work better. I would like to here from people more enlightened them my self on this matter.
That is what I was wondering... whether the standard gap still applied to the boyer system.

Thanks Caulky. I m hip to the temp settings on plugs, etc. Just wanted to confirm the use of ONE resisted component on the micro MK3 boyer system. (ie the "r" in the plug code).

derek
 

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For the Boyer MKIII you use the standard old fashioned copper style wiring with non-resistor caps. Only with the Boyer Micro Digital Ignition do you have to go over to the resistor type wiring and cap. You should not fudge with the gap especially with the digital as you can damage the unit.

As for plugs I use the R type but I have gone to Iridium plugs. Same number followed by an IX suffix. Because these plugs give of such a hot spark they tend to foul less and the manufacturer claims a resultant horsepower fuel economy increase. They seem to last forever. Use 'em in all my bikes. As a further point, the manufacturer recommends not messing with the gap on the iridium.
I now have several sets of still unused platinum plugs.
 

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Just had a quick look at the Boyer Bransden web-site...it says:
"Our Micro Digital and Micro Power ignition systems contain a small computer operating at high speed that can be adversely affected by radio frequency interference. Symptoms can range from refusal to start to intermittent engine stalling symptoms. Use of non-suppressed plug caps has been known to cause permanent damage to the ignition unit."
Yours is BOX00023, KIT00052 for Triumph/BSA 12V twins.

"However, because the Micro Digital features a built in computer..."
Hence it is digital and requires 5K plug or plug-caps.

The plug gap ought to be .025". Larger might produce mis-firing and damage. Smaller, the short duration of the spark may cause incomplete combustion.
 

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"However, because the Micro Digital features a built in computer..."
Hence it is digital and requires 5K plug or plug-caps.
I am certainly not intending question your knowledge on these things (clearly you have long forgotten more than I will likely ever know about these bikes), but would like to get this straight in my thick head...

On the Boyer website they talk about the history and development of the systems. The following quote is used "In 1996, Ernie set about improving and updating the very popular analogue MK3 system, by introducing a microcomputer into it." This would lead me to believe the Mk3 is not "computer" controlled, therefore does not require any sort of resistor cap or plugs (and might even prefer non-resistor bits?)?
 

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Your MKIII is not computer but an analogue unit. This is what Boyer says about their digital and mcro power units (yours being the excluded model)
"Plug caps fitted with suppression resistors are usually fitted to prevent radio interference. radio interference (noise) can cause more complex electronic circuits like radios and computers to malfunction. Our Micro Digital and Micro Power ignition systems contain a small computer operating at high speed that can be adversely affected by radio frequency interference. Symptoms can range from refusal to start to intermittent engine stalling symptoms. Use of non-suppressed plug caps has been known to cause permanent damage to the ignition unit."
I guess the fact that they no longer push the MKIII, they offer less info about it.
 
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