Dominator 99 spark plugs

Previously wrote:

Just got my first Dominator 99. Can anyone tell me the correct spark plugs to use please.

The workshop manual calls for the following:

KLG FE75 or FE80

Lodge 2HLN

Champion N5

NGK B7ES or BP7ES works for me and has done for years. Gordon.

Previously wrote:

Just got my first Dominator 99. Can anyone tell me the correct spark plugs to use please.

Hello Glenn If you see the Green Spark plug man You need to get the new type of spark plug that better the what being mentioned , its a Bosch W7DTC with 3 electrodes not one this give you a cleaner spark and a cleaner exhaust and all with less heat , so the engine stays cooler and runs cooler too and save on fuel too so see the Green Spark plug Co on the web ! I run my Norton 650 on them yours Anna J

Maybe Anna can explain how three electrode plugs work. A spark will always take the route which is closest to the central electrode, so two of the three will never be used. Ever tried tearing a piece of paper in two places at the same time, Anna?

Three electrode plugs are nothing new. I remember an old 350 Triumph we used to ride round a field in about 1962 had a three electrode plug, the bike was a rigid frame one, so it presumably dated from 1950 or earlier.

All that multi-electrode spark plugs achieve are longer life. I don't see the point on vintage machinery as they inhibit effective combustion.

Previously wrote:

All that multi-electrode spark plugs achieve are longer life. I don't see the point on vintage machinery as they inhibit effective combustion.

Any scientific reason why combustion would be affected with vintage machinery? Just curious.

Previously wrote:

Maybe Anna can explain how three electrode plugs work. A spark will always take the route which is closest to the central electrode, so two of the three will never be used. Ever tried tearing a piece of paper in two places at the same time, Anna?

Three electrode plugs are nothing new. I remember an old 350 Triumph we used to ride round a field in about 1962 had a three electrode plug, the bike was a rigid frame one, so it presumably dated from 1950 or earlier.

Hello Well Its to do with Resistances at different speeds of the engine the spark find the best gap the higher the speed of the engine as more revs more power out put from the magneto so it finds a bigger gap better spark that all times cleaner exhaust best combustion result in less fuel used so more MPG and longer last spark plug old tech with a modern twist to it! yours anna j

A spark can only follow the path of least resistance. It can't find a bigger gap - that would defy the laws of physics. It will always go for the smallest gap. With 3 electrodes, the spark will only jump across one. The other two are superfluous. Gordon.

From NGK: http://www.youtube.com/watch?v=53yfHLdn41k

Previously wrote:

From NGK: http://www.youtube.com/watch?v=53yfHLdn41k

Hello You Guys Well it just show you that a 3 electrodes are better than one , your engine runs cleaner and starts better too ! and you save on fuel , and they better for machines fitted with a Lucas K2F or K2FC magneto's So fit Bosch Spark Plugs W7DTC . and find out for you selfs , yours anna j

Previously wrote:

From NGK: http://www.youtube.com/watch?v=53yfHLdn41k

Hello You Guys Well it just show you that a 3 electrodes are better than one , your engine runs cleaner and starts better too ! and you save on fuel , and they better for machines fitted with a Lucas K2F or K2FC magneto's So fit Bosch Spark Plugs W7DTC . and find out for you selfs , yours anna j

Hello NGK B7ES and BP7ES extended nose Are Cold Plus The EQ for Champion N5 is NGK B6ES And both these Plug have suppressors Built in them so No good for Machine With A Magneto

Previously wrote:

From NGK: http://www.youtube.com/watch?v=53yfHLdn41k

Hello You Guys Well it just show you that a 3 electrodes are better than one , your engine runs cleaner and starts better too ! and you save on fuel , and they better for machines fitted with a Lucas K2F or K2FC magneto's So fit Bosch Spark Plugs W7DTC . and find out for you selfs , yours anna j

Hello NGK B7ES and BP7ES extended nose Are Cold Plugs The EQ for Champion N5 is NGK B6ES And both these Plug have suppressors Built in them so No good for Machine With A Magneto

Previously wrote:

Previously wrote:

From NGK: http://www.youtube.com/watch?v=53yfHLdn41k

Hello You Guys Well it just show you that a 3 electrodes are better than one , your engine runs cleaner and starts better too ! and you save on fuel , and they better for machines fitted with a Lucas K2F or K2FC magneto's So fit Bosch Spark Plugs W7DTC . and find out for you selfs , yours anna j

Hello NGK B7ES and BP7ES extended nose Are Cold Plugs The EQ for Champion N5 is NGK B6ES And both these Plug have suppressors Built in them so No good for Machine With A Magneto

Bosch W7DTC As NO suppressors built in them So They Are OK For Machine With Magnetos fitted

Hello You Guys Well it just show you that a 3 electrodes are better than one , your engine runs cleaner and starts better too ! and you save on fuel , and they better for machines fitted with a Lucas K2F or K2FC magneto's So fit Bosch Spark Plugs W7DTC . and find out for you selfs , yours anna j

The video clip shows no such thing!

Anna , much as I value your opinions, I maintain that there is no real point to triple electrode plugs. The spark will always choose the path of least resistance, as shown in the video. Why do you think NGK no longer produce triple electrode plugs? As I originally stated, B7ES and BP7Es have worked for me on my magneto equippped Nortons perfectly reliably for 40 years and 110,000 miles. You are at perfect liberty to recommend other plugs based on your own experiences. Gordon.

If I was Glenn, who asked the question which plugs to use in his newly-acquired Dommie, I would most probably have been content with the first two responses, which both point him in the right direction. However what followed on from there, however interesting,must have him totally confused. I don't profess to have the technical knowledge that some of you have but experience tells me you sometimes have to play around a little bit to get it right, particularly with modern fuels.My own '58 Model 99 is twin carb and coil ignition, and runs best on the hotter B8ES plugs. As far as I understand it, these are NOT resistor (suppressor) plugs - NGK place a letter 'R' in their numbers for those ie BR8ES. If I am confusing my resistors with my suppressors someone please correct me! I do however use resistor-type caps. Hope this helps rather than adds to the melting pot! Martin.

Hi Martin,

I agree with you in saying that "R" means Resistor in NGK world, but to me B8s... are colder than 7, 6 ...(the higher, the colder) whereas in Champion's world, the lower the number the colder the spark.

My 99, 9:1 CR, twin carbs, SS cam, and Boyer analogue ignition, goes fine on Champion N4 which are equivalent to B8ES. I am using 5 k ohm caps. BTW I don't believe there is any reason not to use resistor caps with a magneto.

Whether posts on here are confusing depends on the reader. Some members clearly have very little knowledge about old motorcycles or much experience with spanners. We all started out like that.

Previously wrote:

Maybe Anna can explain how three electrode plugs work. A spark will always take the route which is closest to the central electrode, so two of the three will never be used. Ever tried tearing a piece of paper in two places at the same time, Anna?

Three electrode plugs are nothing new. I remember an old 350 Triumph we used to ride round a field in about 1962 had a three electrode plug, the bike was a rigid frame one, so it presumably dated from 1950 or earlier.

Hello Colin Well These Company's are bring them back with new tech in them to try and clean up the emission coming out off our old bikes and if they help then its OK I found an AC plug the equivalent of Champion N5 with 3 electrodes its AC7C so now that 2 plugs the same as Champion N5 .Bosch W7DTC and AC . AC7C we look for more . And as for tearing a piece of paper in two places at the same time try folding it in half and then tearing it ! its like lightning can strike in the same place twice and lightning can strike in two diffident places at the same time its called a paradox two thing happening at the same time fame . and I bet you had that old Triumph now Yours Anna J

Back in the day, when my 99 was about 9:1 CR, I used Champion N4. N5s are a bit hard. For general touring you will need a softer plug that self-cleans at a lower temperature.

Cheers, Lionel

I'm really disappointed that folks are using the Norton Owners Club web site to discuss Japanese spark plugs.

I use Champion N5 in my 99 and Champion N4 in my 650ss. All my singles (Except 16h) use Champion N5

I have never had a Champion plugfail yet and I can't say that for other makes.

I am sure I read somewhere that Champion plugs contain components which are made in Japan... Anyway, the reason I use NGK plugs is that I had a string of failures over the years with Champions. I reverted to Champions in my 1952 Land Rover and then had plugs fail. Fitted NGKs and it has been fine ever since. That's just my experience but for me reliability is paramount - I don't have a modern bike so I do try and reduce the risk of failure, hence NGK plugs. Sorry to disappoint.

Previously wrote:

I am sure I read somewhere that Champion plugs contain components which are made in Japan... Anyway, the reason I use NGK plugs is that I had a string of failures over the years with Champions. I reverted to Champions in my 1952 Land Rover and then had plugs fail. Fitted NGKs and it has been fine ever since. That's just my experience but for me reliability is paramount - I don't have a modern bike so I do try and reduce the risk of failure, hence NGK plugs. Sorry to disappoint.

Hello my Suzuki 550gt Use to eat NGK plugs I ended up fitting Bosch W7 They were still in when I sold the bike ,

I think Lodge have a good claim to be the most British spark plug company. I have no idea where anything is actually made today; probably China for most stuff.

Lodge Spark Plugs

Rummaging in Grace's Guide is a good way to waste time reminding oneself of lost British industry.