ET: Engine (Twin) Spark Plugs

G.L. Winter

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What are the most suitable spark plugs for a standard B model Rapide which is used at leisurely speeds in a small village and country lanes?
 

kettlrj

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I use Denso W22ES-U plugs on my 'B' Rapide. They are fired by magneto. I set the spark gap at 12 thou. The bike starts easily and runs well with these plugs.
The engine runs with 8:1 compression ratio, Mk2 cams and 1 3/16" TT9 carbs.
Regards Richard.
 

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ClassicBiker

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KLG FE70 if you can get them, sometimes they turn up, if you see them purchase them, better than anything currently produced.

A quick fleabay search will usually turn up some new old stock. But as with anything check the prices carefully. I've noticed some vendors will offer them at low prices but the shipping cost seems to be for a private courier with armed guards. There is a vendor near me who has been asking for $20 for a FE50 and $20 for shipping, totally ridiculous. The two below I found by searching KLG FE70. I usually query "KLG Spark" then spend a little time going through them. Skipping those that are obviously not what I'm after, but double checking those that aren't entirely clear as to what they are. Those that list by the car they fit are a good bet for being reasonably priced. Don't discount those that can be taken be taken apart (detachable) and cleaned "DFE70". It's the same plug.
Doing this I've managed to amass a small stash for my Vins, Triumphs, and MG B without breaking the bank.


 

Gary Gittleson

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I've been using NGK BP6ES for the last three years. They're supposed to be slightly hotter than the FE80 but at least in my case, the plugs are running a bit on the cool side. Otherwise, the NGK's seem fine to me.

So what wonders would I experience by switching to KLG? I did use them in my Norton Atlas all those decades ago. They seemed to work well enough although that Atlas was a beast to start at times. I guess I didn't know enough and/or didn't have enough money to correct the situation back then. The problems were probably in the mag and/or carbs. Compression was fine, as the bruises to my right shin were able to attest.
 

Peter Holmes

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It would be hard for me to tell what wonders might await you if you were to try KLG FE70 spark plugs, probably nothing spectacular, all I can tell you is that they quite simply work for me, I have tried most of the others, NGK, Champion, Nippon Denso, Bosch, etc. and the KLGs seem to work best, they start easier, seem more reliable, and last longer, if I feel the starting performance is going off a bit I give them a quick clean and away they go again, I have a few in reserve and calculate that they will probably see me out, unlike the aforementioned other brands would be likely to manage.
 

Sakura

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It seems unlikely to me that old technology like the KLG FE70 is the answer for every Vincent, and I don't think anyone is suggesting they are. Unlike modern bikes which are basically identical, in each model, every Vincent is now pretty unique, as has been attested many, many times. Therefore most Vincents will "prefer" a particular plug. One size does not fit all.
 

vibrac

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I think in previous iterations on here of this subject its been said that the previous status of NGK being the premium modern plug has taken a dive due to the claim that modern cars with black boxes dont get rich mixtures and so NGK have lowered the capacity of the plug to withstand rich mixtures by reducing the ceramic coating processes that were needed by carburetor engines. And it seems that contrary to the received knowledge of most of my automotive years the dreaded Champion plug has gained ascendancy. That may be true But I must agree nothing looks better than a racing FE75 KLG with a red (pink?)insulator you can just see it peeping out of my spare plug ole' behind my steering damper on the Flash

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G.L. Winter

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Thank you, Stu, for your suggestion. I happen to have some N9YC plugs on hand, and so shall try them. The KLG FE80 plugs I have been running seem a bit too cold for my decidedly relaxed sort of riding.
 
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