Spark Plug Boots

[BillyRok]

I recently purchased these coils and plug wires for an '81, you can see the wires come with new boots that have very little angle where they connect to the spark plugs.

http://www.ebay.com/itm/Dynatek-Dyna...P&vxp=mtr#rwid

The old plug caps have a 90 degree angle at the end and have about 5 ohms of resistance. Should I just cut off the new plug caps on the new wires and screw the old plug caps down onto the wires? Thought I better get some advice before I started hacking things up and later regretting it!

[bikerphil]

I just slightly bent the 1 and 4 boots slightly so they don't stick straight up, the 2 and 3 ones should be fine. I wouldn't cut off those brand new super water tight ends to install caps but that's just me. I also put a piece of 1/4" fuel line over the area of the wire that may rub on the crimp edge of the fuel tank. If you are worried about RF interference, they sell NGK BPR6ES resistor plugs.

[3Phase]

It sort of depends on what spark plugs you're going to use and the condition of your old resistor caps.

For the NGK resistor version of the stock plug BPR6ES or the newer NGK Iridium BPR6EIX and BPR7EIX then just use the wires the way they are.

If you're staying with a non-resistor plug like the stock NGK BP6ES then snip the wires and screw on the caps that came with the bike.

Are all of the internal resistors and all of the little rubber booties good? If not then pick up some new NGK resistor caps and ditch the forty-year-old Denso caps.

[BillyRok]

Ok, so it sounds like the system needs resistance after the coils...either use resistor spark plugs or spark plug boots with resistors built in. I think I'll refrain from cutting up my new wires and use resistor spark plugs. Curious though about why that additional resistance is needed between the coils and mixture ignition. Thanks "smart electrical guys"!

Is it just me or does Scott's avatar seem to be strangely mesmerized by Phil's?

[bikerphil]

You don't need additional resistance, it is just to lessen radio interference. I run these wires and non resistor plugs on both bikes as I do not have an AM radio on the bike. It does interfere with the radio in my shop when I run the engine. The ignition may or may not cause interference to other electronic devices whjch I have not noticed as of yet.

[3Phase]

You can use resistor spark plug wires too but that'd be too easy.

Resistance helps extend spark duration, not just limit RF. Let me see what I can find.

(Google music) Here we go:-

Google Books | Popular Science Jun 1977 |
How to get more power and mpg by installing electronic ignition | Page 180

Guentzler explains why the added resistance is important: "Resistance added to the secondary directly affects rise time." He's talking about the characteristic buildup toward a peak as seen on a oscilloscope. "With low resistance in the secondary, rise time is fairly slow and overall spark duration is shorter. The resistance shortens the rise time and increases spark duration,
which provides extended exposure to the combustible mixture in the gap. This tends to improve mileage and performance."

Poor Gracie, she got turned into a mesmerizing avatar.

[Brak]

I recently rewired my bike, as i was having an intermittent spark issue i now attribute to the graphite core, automotive wires that came with it.

used the NGK LB05F boots for the plugs, and LB05E for the coil.
paired up with a few feet of 7mm copper core wire

i couldn't be happier, install was a snap, and it looks much nicer than those universal kits that leave extra wire dangling all over the place.

and while the initial cost is about the same as a premade set. it only costs a couple bucks down the line, to replace the wire as necessary.

[3Phase]

Yeah, I sort of inherited a set of Accel coils and the included honkin' 8 mm wires that I thought were copper turned out to be graphite.
The wires quit working and for some odd reason so did the ignition.


I use the Iridium resistor plugs so I grabbed some bulk NAPA Belden 7 mm steel core plug wire and brass terminals, then cut to fit.
Even the Accel coils don't generate enough juice to need that much wire and they'll probably outlive me and the bike.


NAPA Belden Spark Plug Wire (bulk) - Tinned Metallic | BEL 734803 $0.69 /Foot


Anyone remember when 1/4" (6 mm) spark plug wire was heavy duty and 7 mm was a high-performance wire?