Author Topic: HT Plug Caps ?  (Read 795 times)

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A10 JWO

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HT Plug Caps ?
« on: 17 April, 2020, 18:09:28 »
My local car spares shop has sold me a plug cap made by NGK ( The only one he had ) . I know nothing about plug caps and their make up. It is a resistor cap SD05F-R 5K. Can someone explain the basic principles of these small parts that play a big role in our engines. Thank you.

idie

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Re: HT Plug Caps ?
« Reply #1 on: 17 April, 2020, 18:35:11 »
Please don't use a resistive plug cap or a resistive spark plug on a magneto system. It will overload the windings with an early failure of the armature. I have played this game it can be expensive.

chaz

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Re: HT Plug Caps ?
« Reply #2 on: 17 April, 2020, 21:04:41 »
the main reason for the resistor caps were to reduce intereference when vehicles passed houses. the resistor cuts the interference and homeowners stay happy. but although ok for modern vehicles they dont like classic bikes or cars, part of the energy is lost.

https://www.ngksparkplugs.co.za/products/ngk-resistor-caps/

A10 JWO

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Re: HT Plug Caps ?
« Reply #3 on: 17 April, 2020, 22:05:25 »
Thanks lads, a learning curve. Keep safe.

TTJOHN

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Re: HT Plug Caps ?
« Reply #4 on: 18 April, 2020, 12:24:47 »
I have used these caps before but I fished out the resistor and put a solid piece of brass rod in its place, you just have to get a pair of rat nose pliers to remove the screw where the lead is meant to go, this is fixed in with what looks like a star retaining washer, I use a piece of small tube to replace, after fitting brass rod.

Regards TTJohn

BEEZABRYAN

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Re: HT Plug Caps ?
« Reply #5 on: 18 April, 2020, 13:26:51 »
Hi John, I've always bought non-resistor plug caps.
Saved a lot of buggering about.
 :P

Dean Southall

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Re: HT Plug Caps ?
« Reply #6 on: 18 April, 2020, 15:25:54 »
If using Boyer Bransden electronic ignition you should use resistor spark plug caps. Although not essential for MKIII and MKIV they protect the elcetronics of the igntion system from interference.
BSA: turning ordinary men into mechanics since 1910

A10 JWO

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Re: HT Plug Caps ?
« Reply #7 on: 18 April, 2020, 16:19:53 »
Thanks Dean I have a Mark IV and a Pazon Mark 8 on my other one, more knowledge, thank you.

Editor

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Re: HT Plug Caps ?
« Reply #8 on: 19 April, 2020, 12:38:33 »
Yes, thanks Dean, Having just fitted BB ign to the A50, I was going to change the caps to none resisitor, but I'll keep the NGK caps now.

Old Biker

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Re: HT Plug Caps ?
« Reply #9 on: 19 April, 2020, 16:19:44 »
Need to make sure you don't use plugs with in built resistors along with the resistor caps, one or the other with BB ignition

BEEZABRYAN

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Re: HT Plug Caps ?
« Reply #10 on: 20 April, 2020, 05:11:10 »
The Flash & a Box has non-resistor plugs & plug caps, the Infamous Enfield (Boyer ignition) has an iridium resistor plug with non-resistor plug cap.
« Last Edit: 20 April, 2020, 05:13:07 by BEEZABRYAN »