1961 super rocket spark plugs

[Rob jones]

Hi could anyone tell me which spark plugs to use on a 61 super rocket,it's got champion n3 in it at moment is this correct cheers

[lawnmowerman]

Hi Bob and welcome to the forum.

N4Cs work for me although I have run on NGK B7ES. There have been many reports on the forum regarding new plugs which are duff straight out of the box although the upside is that they are fairly cheap nowadays.
I get my plugs from the Green Spark plug Company. Tim Green is very helpful and knowledgeable and has a huge stock. I have no connection but have always bought from him in the past.


Jim

[Beezageezauk]

Hi Rob,

I haven't checked the differences between the set up of the 61-62 SR's but the BSA Twin Restoration Book (Roy Bacon) shows Champion N3 or NGK B8ES for 1960 & 61 models with Champion N4 or NGK B7ES for 1962 & 63 models.

Beezageezauk.

[metalflake11]

I use B6ES when I am stuck, which as Jim says are cheap and unreliable. I try to get hold of Denso W20ES-U as recommended by S.R.M. as a preference. You may need to experiment though, mine eats Champion plugs immediately but many others have no problem.

[metalflake11]

The problem with that though Beezageezauk, is that the book was published in 1996 when they still sold petrol, correct me if I am wrong, but 3/8" BTDC is the timing figure shown? That is also incorrect these days in the UK.
                           Rob.

[wardleybob]

I use denso w22esu and I have never had any probblems I run with a 26 mill makuni .I get good starting and 70  +mpg.wardleybob

[A10 JWO]

Whilst we have experts on plugs here, what should be in my standard 1954 A10 Flash. Did not want to start another thread whilst you chaps are about.

Ta Colin

[BSA_54A10]

It will depend upon the compresson ratio, the condition of your engine ( wear ), your location , the type of riding you do, ( I could go on  but I won't ) .
These all come into play which is to a large part the reasons why particular people find one brand of plug better in their bike than another.
You start at what was recommended by BSA then have a look at your plugs.
If you motor always seems to be pre-igniting or melting either the electrode or insulator then you go down a grade.
If the plugs continually soot up then you go up a grade till you are happy with the results.

There is no profit in making modern standard plugs and the quality of the plugs on sale now days refects this.
Most plug factories make a dozen or more different brands of lugs.
The last thing that is done before they get packaged is printing the name & grade on the plug and each plug is tested so the best ones go into the individual boxes and the wore ones go into the bult packs of "home " branded plugs.
Some plugs will work well over a large range Denso are the best at this .
Champions tend to work better over a wide rage than NGK's but there a lot more grades of NGK's than Champions and in some ranges there are 4 NGK's spanning the same range as 1 Champion.

The quality of Bosh plugs seems a bit better than Champs or NGK's but I have had some Bosh's go bad straight out of the box as well.
None of the plugs are equivalent to each other which is where all of the conversion spread sheets get it wrong.
I did see a pair of bar graphs which was quite good as it clearly showed the N4's & N5's spanned 4 grades of NKG and N4's / N5's themselves had a lot of overlap.

[duTch]

   I found this link on a other forum through a Google search- don't wear your cross eyes

http://www.gadgetjq.com/spark_plug_cross_reference_motorcycle.htm

[saltbox Alf]

Crikey Dutch, had to go lay down for a while after looking at that chart!

In my '61 rocket I use Champion n4s seems to run well with them, it don't like ngk's misses and spits with them. as previously said ,just try different plugs and see what it's happy with

[duTch]

 Hiya Alf, sorry 'bout that- should've said maybe make sure you DO wear your cross eyes...!!!???
   I went to procure some N3 's but seems they aren't so available(at least in my neck'o the woods), Could've maybe had N4C (next day- can't remember, maybe got impatient), but to compare at some stage, bought N9YC and NGK equivalent BP7ES,. The difference being the 'P' denotes 'projecting tip'- supposedly exposes the tip and provides better fire...hey I'm no expert, just goin' on what I read here and there, but I run 'em in My Gutzi, and they work ok, and the hundred miles or so I've done the last few days, they seem to work ok.....so far.....! had to drop the needle a notch, seems better starts one kick-no prime if warm, need to adjust the clutch(a bit slippy)...but that's delving into 'off topic', so more later.! cheers, duTch