Classic British SparesKlempf British PartsBaxter CycleBritBike Sponsor SteadfastCyclesSRM EngineeringLucas Classic MotorcycleHepolite PistonsIndustrial tec supply

Upgrade your membership to: Premium Membership | Gold Membership | Life Membership | Vendor Membership | Site Sponsor Membership
Welcome to BritBike Forum!
Britbike forum logo
Member Spotlight
KarlB
KarlB
Kent
Posts: 2,184
Joined: August 2005
ShoutChat
Comment Guidelines: Do post respectful and insightful comments. Don't flame, hate, spam.
Search eBay for motorcycle parts in following countries
Australia, Canada, France, Holland, Italy, United Kingdom, USA
Previous Thread
Next Thread
Print Thread
Page 1 of 2 1 2
#835241 01/02/21 8:03 pm
Joined: May 2020
Posts: 139
Likes: 12
R
Ragmanx Offline OP
Britbike forum member
OP Offline
Britbike forum member
R
Joined: May 2020
Posts: 139
Likes: 12
Which plug would you prefer for my '68 Lightning ?
Thank you
SteveG

Last edited by Ragmanx; 01/02/21 8:04 pm. Reason: spelling
Support Your #1 BritBike Forum!

Check out British motorcycles for sale: British Motorcycles on e-Bay UK, British motorcycles on e-Bay North America
Joined: Mar 2006
Posts: 4,117
Likes: 23
R
Britbike forum member
Offline
Britbike forum member
R
Joined: Mar 2006
Posts: 4,117
Likes: 23
i use champion N4G in mine


1972 Triumph T120
1968 BSA A65
1968 MGB Roadster
1979 Chevrolet Camaro Berlinetta
1969 Honda Mini Trail
1939 farmall f30 tractor
2004 Honda Shadow Aero

1975 yamaha xs650b
1972 Norton commando
2 olive drab WWII military bicycle replicas
Joined: Oct 2006
Posts: 4,122
Likes: 70
I
Britbike forum member
Offline
Britbike forum member
I
Joined: Oct 2006
Posts: 4,122
Likes: 70
Weren't Champ N4 plugs directly specified for BSA A65s? ?

Joined: Oct 2001
Posts: 1,783
Likes: 172
S
Britbike forum member
Online Content
Britbike forum member
S
Joined: Oct 2001
Posts: 1,783
Likes: 172
N3 was standard, but N4 works fine as well for normal riding.

Joined: Mar 2006
Posts: 4,117
Likes: 23
R
Britbike forum member
Offline
Britbike forum member
R
Joined: Mar 2006
Posts: 4,117
Likes: 23
i ride 'moderate' speeds use the N4Gs in all my bikes they work great the N3s were too cold...but that's just my experience


1972 Triumph T120
1968 BSA A65
1968 MGB Roadster
1979 Chevrolet Camaro Berlinetta
1969 Honda Mini Trail
1939 farmall f30 tractor
2004 Honda Shadow Aero

1975 yamaha xs650b
1972 Norton commando
2 olive drab WWII military bicycle replicas
Joined: Aug 2001
Posts: 350
Likes: 9
P
Britbike forum member
Offline
Britbike forum member
P
Joined: Aug 2001
Posts: 350
Likes: 9
If I recall correctly, BSA had specified Champion N3 for the Lightning, N4 for the Thunderbolt.

I run Champions N3C in my Lightning and the Firebird, the plugs are absolutely fine and troublefree.

There is a chance that Federal Mogul has changed or will change the type designation for the plugs, I have read the N3C would be listed as Champion 801C in the future. Slightly confusing but no worrisome.

HTH

Cheers!

Phil

Last edited by Phil in Germany; 01/02/21 10:37 pm.

Best regards
Phil
Duesseldorf/Germany
'62 A 65 Star (disassembled)
'69 A 65 Lightning
'71 A 65 Firebird
'84 Yamaha SR 500
Joined: Mar 2006
Posts: 4,117
Likes: 23
R
Britbike forum member
Offline
Britbike forum member
R
Joined: Mar 2006
Posts: 4,117
Likes: 23
should have said my 68 A65 bitsa is single carb....


1972 Triumph T120
1968 BSA A65
1968 MGB Roadster
1979 Chevrolet Camaro Berlinetta
1969 Honda Mini Trail
1939 farmall f30 tractor
2004 Honda Shadow Aero

1975 yamaha xs650b
1972 Norton commando
2 olive drab WWII military bicycle replicas
Joined: May 2020
Posts: 139
Likes: 12
R
Ragmanx Offline OP
Britbike forum member
OP Offline
Britbike forum member
R
Joined: May 2020
Posts: 139
Likes: 12
Thanx for all the replies.
My bike, with C3's, was getting hard to start in the cold. Removed and cleaned the plugs. Replaced them and it started right up with help from the choke.

I ordered two C4's from WallyWorld for $9 including shipping to try them out.

The BSA work Shop Manual calls for C4 plugs.

So all is well and you guys opinions backed that up.

Thanx again
SteveG

Joined: Mar 2006
Posts: 1,678
Likes: 16
H
Britbike forum member
Offline
Britbike forum member
H
Joined: Mar 2006
Posts: 1,678
Likes: 16
Factory Manual says NC3 for Lightening, NC4 for Thunderbolt. Which is a bit strange because the engines at least in the late sixties bikes were identical except for the carbs and the tach drive. Maybe they figured the Thunderbolt was the sedate tourer and need a slightly hotter plug. Probably either will work in either bike except maybe a preference for the 3 when doing a lot of higher speed riding in hot weather.

Last edited by htown; 01/03/21 3:10 am.

1978 Bonneville T140E
1974 Trident
1970 BSA Thunderbolt
1971 Norton Commando
1972 Norton Commando
1973 Norton Commando
1974 Norton Commando
2018 Kawasaki Z900RS


Everything will be alright in the end. If its not alright, its not the end.
Joined: May 2020
Posts: 139
Likes: 12
R
Ragmanx Offline OP
Britbike forum member
OP Offline
Britbike forum member
R
Joined: May 2020
Posts: 139
Likes: 12
Thanx for your reply.

The work shop Manual that I have says Champion N4 for the A65 Lightening. Page GD 11.

From all the responses I read, I think the are very comparable. Probably depends on the owner and their particular bike.

I will run theC3's (now cleaned) and try the C4's when they arrive.

SteveG

Joined: Oct 2001
Posts: 583
Likes: 7
O
Ola Offline
Britbike forum member
Offline
Britbike forum member
O
Joined: Oct 2001
Posts: 583
Likes: 7
Many plugs will fit the A65. The question is, what plug will fit the rider?

Regards


There are no bosses in a technical discussion
(Doug Hele, 1919 - 2001)
Joined: Mar 2005
Posts: 10,656
Likes: 75
J
Britbike forum member
Offline
Britbike forum member
J
Joined: Mar 2005
Posts: 10,656
Likes: 75
There is much confusion when it comes to plugs. A change in grade of spark plug can be required because of changes made to the engine. Raising or lowering compression is one such example. But change the factory recommended plug because a plug fouls either from fuel or oil is not a wise decision. This especially true if the fouling is fuel related.

Take a Mikuni VM or one of the AMAL series carburetors. There is one throttle position we use the most. That is between 1/8 and 1/3 throttle. This is where the straight portion of the needle sits in the needle jet's orifice. Because the the needle moves back and forth, sliding on the brass jet, with each change in air flow as the piston draws air into the cylinder. This cause the inside diameter of the jet to enlarge over time. This leads to a rich condition in only a narrow part of the power band. The one most of us use the most: the point where the straight portion of the needle is in the needle jets orifice.

This incidental enrichment can cause the factory recommended spark plug to foul. This is happening not because you are using the wrong plug, but because the real fault is not being addressed.

Why is this important? When you changed the grade of the plug to cure the rich condition at low throttle openings the jetting when the taper takes progresively returns to normal with no change from factory jeting as the slide approaches 3/4 throttle.

So the first time you open the throttle above 1/3 throttle without the bike increasing speed (this is what is called lugging) your hotter plug that was a cure for low speed fouling now becomes a problem. It puts you one step closer to destructive detonation and detonation induced pre-igntion.

Oil fouling can create the same problem. Oil or fuel fouling is not a problem to be solved by changing plug grades! If the factory recommended plug doesn't work, and you foul plugs (either fuel or oil) it is not the plug's problem.

I see another post where someone wants to use a hotter grade plug because it has got cold and he has to use the choke. This is not a plug problem! In a properly jetted engine it is normal to have to choke the carburetor to get the engine running.

4 members like this: The Bonneville Shop, Ragmanx, Shane in Oz, Allan G
Joined: May 2020
Posts: 139
Likes: 12
R
Ragmanx Offline OP
Britbike forum member
OP Offline
Britbike forum member
R
Joined: May 2020
Posts: 139
Likes: 12
Thanks for your good insights.

I suspect I maybe be the cause of my problem by tickling the carbs too much, thinking that the engine was being starved of fuel.
Thereby fouling the plugs.

I say this because after I cleaned the plugs, the bike fired right up.

The weather here is pretty bad and I cannot ride enough to really make any meaningful determinations.

The plan , weather permitting, is too continue with the C3's. The book calls for C4's and I have some coming. Then will go from there.

Thank you,
SteveG

Joined: May 2013
Posts: 8,015
Likes: 148
A
Britbike forum member
Offline
Britbike forum member
A
Joined: May 2013
Posts: 8,015
Likes: 148
It’s already been mentioned but Lightning’s and other more sporting twin carb variants got N3’s and touring bikes for N4’s.

I’ve found that both bikes are happy on N3’s. I’ve ran my lightning on N4’s.... but it does seem happier on N3’s


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Joined: May 2020
Posts: 139
Likes: 12
R
Ragmanx Offline OP
Britbike forum member
OP Offline
Britbike forum member
R
Joined: May 2020
Posts: 139
Likes: 12
All good insights.

I'm getting conflicting info. Which plug is hotter?

Joined: Mar 2005
Posts: 10,656
Likes: 75
J
Britbike forum member
Offline
Britbike forum member
J
Joined: Mar 2005
Posts: 10,656
Likes: 75
N4 is hotter than an N3.

Joined: May 2020
Posts: 139
Likes: 12
R
Ragmanx Offline OP
Britbike forum member
OP Offline
Britbike forum member
R
Joined: May 2020
Posts: 139
Likes: 12
Thank you.

Joined: Aug 2001
Posts: 5,613
Likes: 71
M
Britbike forum member
Offline
Britbike forum member
M
Joined: Aug 2001
Posts: 5,613
Likes: 71
Another thing that was not mentioned is the change in fuels over the years. These days the rims of the plugs are always black even if the porcelains are light tan to white. As I recall, in the "old days", I could achieve a tan color all over the plugs.

I have always run the highest octane fuel I can get at the pump, which today is 93.


Mark Z

'65(lower)/'66(upper, wheels, front end, controls)/'67(seat, exhaust, fuel tank, headlamp)/'70(frame) A65 Bitsa.
Joined: May 2013
Posts: 8,015
Likes: 148
A
Britbike forum member
Offline
Britbike forum member
A
Joined: May 2013
Posts: 8,015
Likes: 148
That sounds like a rich idle mixture or high float level Mark if you have dark rings on the plugs. If you remove a plug from a car with fuel injection then the whole plug metal area will be a nice tan colour.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Joined: Mar 2005
Posts: 10,656
Likes: 75
J
Britbike forum member
Offline
Britbike forum member
J
Joined: Mar 2005
Posts: 10,656
Likes: 75
Quote
I have always run the highest octane fuel I can get at the pump, which today is 93.

That 93 number on the pump is not the fuel's octane rating!!It is the anti-knock-index. A US fuel with a 93 AKI will have a RON (research octane number) of 98.

Using RON as a target, which is the number we used in the US for decades, the highest pump gasoline you can get is 98 RON (plus or minus a bit).

Joined: Oct 2008
Posts: 7,167
Likes: 134
Britbike forum member
Offline
Britbike forum member
Joined: Oct 2008
Posts: 7,167
Likes: 134
From my experience reading plugs is nothing but confusion.
When I installed new Premiers on my Trident I immediately went out for a ride, holding the throttle at a constant opening I got plugs which looked perfect, ashen colored with a good color ring when viewed through an otoscope. Tuned the idle mixture using the Color Tune. Ever since the plugs come out black.
FWIW I use N4's in my A65. The deposits start just at the bend in the electrode.


Knowledge speaks. Wisdom listens.

72 T120V cafe project "Mr. Jim"
72 T150V "Wotan"
92 BMW K100rs "Gustav"
Joined: Jan 2014
Posts: 1,501
Likes: 139
N
Britbike forum member
Offline
Britbike forum member
N
Joined: Jan 2014
Posts: 1,501
Likes: 139
These days it's better to see some colour on the plug, err on the safe side
unless you can guarantee the fuel you buy is good. The poofteenth of power
lost is worth not holing pistons.

Joined: May 2013
Posts: 8,015
Likes: 148
A
Britbike forum member
Offline
Britbike forum member
A
Joined: May 2013
Posts: 8,015
Likes: 148
Originally Posted by NickL
These days it's better to see some colour on the plug, err on the safe side
unless you can guarantee the fuel you buy is good. The poofteenth of power
lost is worth not holing pistons.

More likely to see some colour with the right mixture on the right plug than a suspect or right mixture on a hotter plug.. and you minimise the risk of holing pistons.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Joined: Dec 2013
Posts: 5,745
Likes: 116
DOPE
Offline
DOPE
Joined: Dec 2013
Posts: 5,745
Likes: 116
my go-to plug for most purposes has always been the NGKB8ES. but its been discontinued. i thought about spending a bunch of money for some to use up, but unless i spend several hundred bucks on those and a lot of B9s i'll have to get an alternative pretty quick anyway.

i suppose i'll go back and see whether the champions will work for me this time around. i gave up on em years ago but maybe it was just me.

in the meantime i don't know what to do about the magneto machines, as the NGK replacements for the B8ES and B9ES aren't reccommended for magnetos.


i'm old enough to remember when patriotism meant not trying to overthrow the government.
Joined: May 2004
Posts: 4,842
Likes: 75
B
Britbike forum member
Offline
Britbike forum member
B
Joined: May 2004
Posts: 4,842
Likes: 75
Originally Posted by kevin
my go-to plug for most purposes has always been the NGKB8ES. but its been discontinued. i thought about spending a bunch of money for some to use up, but unless i spend several hundred bucks on those and a lot of B9s i'll have to get an alternative pretty quick anyway.

i suppose i'll go back and see whether the champions will work for me this time around. i gave up on em years ago but maybe it was just me.

in the meantime i don't know what to do about the magneto machines, as the NGK replacements for the B8ES and B9ES aren't reccommended for magnetos.

I think you willfind it has been replaced with the BP8ES
Most standard plugs are being replaced with the projecting electrode type "P" .
Unless you are running bigger pistons than 10:1's or have shaved the head past its functional limit they should clear the pistons.


Bike Beesa
Trevor
Page 1 of 2 1 2

Moderated by  Allan G, Jon W. Whitley 

Link Copied to Clipboard
Job CycleBritish Cycle SupplyMorries PlaceKlempf British PartsPodtronicVintage MagazineBSA Unit SinglesBritBike SponsorBritish Tools & FastenersBritBike SponsorBritBike Sponsor






© 1996-2021 britbike.com
Powered by UBB.threads™ PHP Forum Software 7.7.5