• Welcome to the website of the Vincent H.R.D. Owners Club.

    Should you have any questions relating to the Vincent H.R.D. Owners Club, or Vincent H.R.D. motorcycles in general, please contact Graham Smith, Hon. Editor and Webmaster by calling 07977 001 025 or please CLICK HERE.

    You are unrecognised, and therefore, only have VERY restricted access to the many features of this website.

    If you have previously registered to use this forum, you should log in now. CLICK HERE.

    If you have never registered to use this website before, please CLICK HERE.

spark plugs

derek

Well Known and Active Website User
VOC Member
Which is considered the best plug for a Comet with magneto.
I believe that fine wire NGK plugs operate at a lower votage, It was recommended to use a B6EV : But they are not now available.Thanks Derek.
 

Alan J

Well Known and Active Website User
VOC Member
I use NGK BP7ES in all my bikes! Old B.S.A. A.J.S, Morini and "me vin" the best all round plugs there are!! pity they are from "nipon!"
 

roy the mechanic

Well Known and Active Website User
VOC Member
N G K bp7es sounds a bit too much. the rap runs bp6es,all depends how oily you motor is. Techniv is dead right, No supressors of any kind with a "prince of darkness" mag! Roy.
 

Tom Gaynor

Well Known and Active Website User
VOC Member
NGK's recommendation for Rapides, Shadows, and Lightnings (and the single equivalents) is the BP6 - I have an obsolete NGK plugs booklet which gives recommendations for every old bike known to man. Grade 6 plugs are recommended for virtually everything. However if your plugs are oily, and you don't want a rebore and new valveguides just yet, a twin will run all day on the hotter BP5, which is hot enough to burn the oil off. (I've since bitten the bullet so have reverted to 6's again.
Caveat: I've been using NGK since 1974 with no problems. In the last 5 years I've had 5 fail, 4 of them in the last 2 years, all BP6 type, and all four almost new - mostly 2 or 300 miles. The last one was yesterday, after about 50 miles. It still has shiny plating on the thread.
 

mercurycrest

Well Known and Active Website User
VOC Member
I've been using Champion N-5c (which are now re-numbered 120c) for the last thirty plus years. I used to throw them out and replace them once a year. Npw, I just replace them with a cleaned pair and run last year's through the glass beader, check the gap and store for the next plug change. I doubt if I've bought a plug in at least the last five years.

Cheers, John
 

Tom Gaynor

Well Known and Active Website User
VOC Member
Mag on the Vincent (two plugs) coil on the Sunbeam S7 (two plugs), and electronic on the Ducati. And jumping ahead, nothing wrong with any of them. What is odd is that none of my old NGK plugs have EVER failed. Maybe they've been "improved"....
 

Tnecniv Edipar

Well Known and Active Website User
Non-VOC Member
Frequently failing plugs can be a sign of weak spark. It's difficult to know a mag is ok unless it's checked on a test rig. Mags do need regular servicing to maintain them at full performance . Mag servicing was generally mentioned in owners manuals , Lucas & Miller had service exchange schemes for customer convenience.
 

Tom Gaynor

Well Known and Active Website User
VOC Member
2MTT's (Lucas racing mags) need to be overhauled every couple of years. They usually signal their need by cutting out when they get seriously hot, but starting first bump after a few minutes. Don't ask how I know this, but I run a PVL system now, with the mag as spare.
I think that until relatively recently mags were prone to fail soon (two or three years) after overhaul because the new condensers were crap and not fit for (magneto) purpose. I believe that Dave Lindsley had proper ones made.
However, while it is possible that both the twin mag AND the Pazon powered Sunbeam are going to glory, I'm blaming new NGK plugs for now.
 

John Appleton

Well Known and Active Website User
VOC Member
Tom Gaynor;1560 I'm blaming new NGK plugs for now.[/QUOTE said:
Tom, a slightly different situation, and I would not presume to try to change your mind, but in the course of any week we probably fit upwards of 60 new spark plugs, and possibly closer to 100. All of these are NGK of various types and in different applications. I cannot remember when we have ever had a failure due to substandard plugs.
What we do occasionally get is a plug which refuses to spark after an engine overheat situation. Another point I would like to bring up is the blast cleaning of plugs, which process I have seen mentioned on this thread. This has not been reccomended for many years as the blasting is likely to marr the glaze of the ceramic insulator, thus offering an earth path away from the plug electrodes.
 

Tom Gaynor

Well Known and Active Website User
VOC Member
John: thanks for that, I value your input since you have a lot more motors through your hands than I ever do! Today I dug out the new NGK BP6EPZ that failed on Sunday, after about 50 miles on the coil ignition, electronically triggered by Pazon, S7, and wiped (wiped...) the carbon off with a rag. I then tested it in my plug testing device. The untutored eye could easily mistake this for an original BTH mag off a 1930's Rudge, but of course it is really a miniature Hadron Collider (which would be a great name for a sixteener moped) with reverse suction transistorised widget valves. I hope you are suitably impressed.
Zilch. Nada. Nothing. The ancient Bosch plug, the Champion N5 (so old it's an N V), the much older NGK BP VI all produced a fat blue spark. (The mag isn't motored, I just flick the sprocket over by hand.)
What is particularly annoying is that in 30 years, no, dammit, 36 years, I have had to buy almost NO BP6's because they last forever, so have few used spares. In the last two years I've started being greeted at the door of Halfords by the manager.
I have any number of B10EV (TZ Yamaha) plugs, maybe 20. So if someone wants to make me an offer, little used, new for every start, I can pop round to Halfords again and buy some more BP6's...
 

mercurycrest

Well Known and Active Website User
VOC Member
Another point I would like to bring up is the blast cleaning of plugs, which process I have seen mentioned on this thread. This has not been reccomended for many years as the blasting is likely to marr the glaze of the ceramic insulator, thus offering an earth path away from the plug electrodes.[/QUOTE]

Hi All,
I wondered what happened to all those plug cleaning machines motorists used for eighty or more years. So far this hasn't happened to me with my cleaned plugs. It sounds more like a marketing theorythan an engineering theory to me. I promise I'll tell you if and when it does happen. :)
Cheers, John
 
Last edited:

John Appleton

Well Known and Active Website User
VOC Member
Yes all understood Tom . I guess what I was really doing was suggesting(diplomatically, for me ) that it is not necessarily the plug faulty in the first instance, but some other factor on the bike causing the plug to become faulty. John
 

John Appleton

Well Known and Active Website User
VOC Member
[QUOTE=mercurycrest;

Hi All,
I wondered what happened to all those plug cleaning machines motorists used for eighty or more years.

John, I think you will find them under the bench alongside cans of flushing oil, tins of upper cylinder lubricant, Holts liquid decarboniser and Holts liquid rebore. All covered in dust and cobwebs , but far too precious to get rid of.
John
 

vin998

Well Known and Active Website User
VOC Member
VOC Forum Moderator
Tom,

I have had a similar problem to you with NGK plugs. Ran BP6ES in the rap for 15 years no problems, then 2 years ago I treated the vin to a new set and one was faulty out of the box. Got it replaced and then had another failure after 75 miles. Put the old plugs with 15000 miles on them back in and ran no problem. It might have been just a batch problem, but I decided that as reliability is key I swapped to Champion N5 and have had no problen in the last 7000 miles.

Cheers, Simon.
 

Tom Gaynor

Well Known and Active Website User
VOC Member
Funny: I've done exactly the same. Found a couple of old N7Y plugs today, and put them in the panniers as spares!

Apropos plug prices: at the rate I cost my time, and the cost of fuel, the motor factor costs whatever he costs, plus £20. Halfords is about £18 cheaper for four plugs. And I can pop in to Lidl across the road and buy a CNC machining centre and a pack of decent German sausages and still have change out of the £20 I didn't spend going to the factors.

I looked at plugs today while in Halfords buying grease. Looking at the NGK display, 98% of the plugs had "an R in them". I can never remember whether one should or should not eat oysters if there's an R in the month, but know that one should never subject magnetos to NGK plugs with an R in them, and expect that it's the same for Champion and Bosch even if their nomenclature is less overt. Expect autojumble prices of used plugs to soar when this news gets out.
 
Last edited by a moderator:

Tnecniv Edipar

Well Known and Active Website User
Non-VOC Member
I suppose it depends on how close motor factors are to you. Luckily I have several on route to destinations I frequently travel to. Then there are always online suppliers.
 

Can't Find What You Need?

Buyer Beware: Fake or Real?

Top