Britbike forum Forums British Motorcycle specific Brands Bsa bulletin board Best Spark Plug for BSA 441 Victor Special

I have a newly acquired 1969 BSA 441 Victor Special. The manual calls for a Champion N4 spark plug. I've looked at several references that say that a Champion N4-C is not compatible with my engine. Years ago I had a BSA Gold Star and I had difficulties with Champion plugs going open internally, I'm assuming from vibration. I also burned a hole in a piston in a 74 Trident I had, apparently from too hot a plug. I finally had the best luck with NGK plugs holding up in my Gold Star. I also had good luck with Autolite plugs. What is the best plug to use in my 441 Victor? I have read a considerable amount of conflicting information.

Where did you read that the N4C wasn’t compatible? The standard N4 is no longer available and the N4C is the direct (C meaning copper core) replacement.

The N4 part of N4C is dimensionally and heat range identical to the old N4.

NGK BP5ES

I looked on three different sites advertising spark plugs on Ebay that listed motorcycles. When I entered 1969 BSA 441 Victor Special all came back and said N4-C wasn't compatible. Each one of those sites looked like they used the same software. I was surprised since the Champion site said that N4-C was the replacement for N4.

Don't expect ebay seller databases to properly cover an over 50 year old motorcycles. As Allan says the N4-C was a direct replacement for the N4 with a copper core, it can hardly be incompatible with a B44. My B44 is twin plugged so no point in giving you my plug numbers as its non standard in that and a few other ways.

I should know better than say anything but that’s hard for me to do.

Larry’s plug is 3 heat ranges hotter (?) than the plug I use. Unlike kommandos bike mine are all pretty much stock.

This darn “no longer produced” stuff with plugs is a pain. I’ve been doing some research today and I’m getting conflicting information on the plug cross overs.

It used to be simple.

Gordon

I usually use NGK plugs in my B44 and the equivalent based on the heat rating of N4 is B7ES.

Note that the heat rating of Champion plugs is opposite to NGK, so the lower the number of a Champion plug the colder the plug is (e.g. N3 is colder than N4), whereas NGK works in the opposite direction with a higher number indicating a colder plug (e.g. B6 is hotter than a B7).

There are various spark plug cross reference sites available like This One, where you can get an approximate equivalent.

I don't think these sites are 100% accurate, so if you're using a Champion to NGK (or other) equivalent plug grade its worthwhile trying a heat range slightly higher or lower and checking the plug condition.

Another factor is modern fuel which can often foul a plug, so using a hotter plug can be beneficial, I've used NGK B6ES without issue.

You shouldn’t try to use hotter plugs to try and clean a plug other than what is specified for your engine.

If you understand what the make up of motor gasoline is, you’ll probably find that it is less likely to foul a plug. There are many solvents in motor gasoline which make up the final product, toluene, isooctane, xylene ( and in some cases ethanol) etc if the “carburettor is jetted correctly” you should find that the plugs are more likely harder to read than they were on the motor gasoline produced 50 years ago. You could probably get away with changing a plug one heat range different to the other. However using the wrong heat grade will cause damage to the engine long term.


Other contributing factors are a worn out carburettor.

That’s exactly what I’m talking about…….confusion.

I guess spark plugs are going the way of oil……use any damn one you want….they all do the same thing????

Site I used ( today) clearly says BOTH the B8 and B7 are replacements for N4. How can that be?

Confused in NC…….I knew better.

Gordon

That’s some Mileage in one day on an old beeza, most I’ve done is 300 and I was pretty well worn out by then. Bike was fine but I was ready for a beer or several.

I have a bsa article somewhere which kinda agrees with your B8ES =N4, though modern cross references say different. In this particular article it goes on to show the N3 equivalent is equal to B9ES.

Well I think I got some of it figured out…….all B44s are not created equal. My road going B44s are 1967 Roadsters ( Larry’s too I think). My owners manual says it uses a different plug ( N6Y) than the OPs 1969 VS N4

quiten, you got a cross reference for the N6Y??? I don’t trust anything I’m reading now.

Allan my friend, I’m one of those fellows that doesn’t get into the zone until after the first 100 miles.


Gordon

Correction!!!! Ruperts says N6Y for the 67 VR.......owners manual says N4......more confusion

Apparently NGK and Champion spark plug numbers are about half a heat range offset from each other+ as well as running in opposite direction, so the Champion N4 is about an NGK B7.5E* and the N3 is B8.5E*. Alternatively, an NGK B8E* is about a Champion N3.5 and the B7E* is about a Champion N4.5.

Just in case we weren't confused enough already, Champion's 'N' is 14mm, 3/4" reach (yes, they really do mix metric and imperial), NGK's 'B' prefix is 14mm and 'E' suffix is 3/4" reach

[+] I read that years ago, but don't remember where, or even if the source was trustworthy. Take it with the appropriate sized grain of salt.

Now that I'm home and to totally confuse ME even more.........the plug I've been using in my 1967 B44R is a NGK BP8ES. Ruperts says Champion N6Y

My info says B7ES for 70-68 VS and SS.........replaces (owners manual) Champion N4

My 1967 C25 uses NGK B8ES........replaces (owners manual) Champion N3

NUMBERS CONFUSE ME

Wonder if Larry's post is a typo? No where can I see going that hot......and I really shouldn't write a reply from my phone at work.

I'm done.....as long as it sparks and lifts your skirt......go for it.

Gordon

PS......to try and answer the OP's original question a Champion N4C should work fine in a healthy B44VS IMO

I don't trust Champions much these days. Too many defective ones. My B44 and B50 both live happily with B8ES's. They are mostly desert ridden which means more revs, more lugging and more heat. I have had no fouling problems and haven't holed any pistons but I do use race gas. A B7ES would probably be just fine for break-in or for lower speed riding.

Like Gordon, I wouldn't use a BP5ES in one of these bikes.

NGK BP plugs are a projected electrode type.If the piston crown doesn't hit the electrodes, it will put a hot spot close to the piston crown

I have run projected spark plugs in Unit Singles for 40 years (C15,B25,B40,B44), never had a hole in a piston or the gap close up.

Just to confuse Gordon even more, NGK no longer makes non resister plugs.

Try to order a b7es or bp7s and see what you get

so ...... I tried all sorts of combinations of letters and numbers on those sparky things made by NGK. could not get any of them to work worth a damn on my '67 B44.
Bought some Champion N4C and found the starting, and running, hot or cold to be easy and reliable. No sign of over or underheating. Of course at the same time I also abandoned attempting to resurrect the 52 year old carb and contact breaker set, new carb and Vape ignition might have had something to do with it!
Did not take the chance or was willing to experiment on the next B441VS.

I had a 72 B50 years back. I always carried a spare plug with me due to high failures, mostly with Champion. I don't remember the plug number I was using. The plugs would always look perfect, but no spark. I must have had somewhere between 5 and 10 plugs go bad on me with that B50 before I sold it. I remember one trip through the Blue Ridge Mountains in North Georgia and North Carolina. Several hundred miles in one day. On the way home at around 10:00 PM in the absolute middle of nowhere, the B50 shut down. Pitch dark and no traffic to flag down for help. No spare plug. I pushed the bike back into the weeds so no one could steal it and walked about 5 miles down the road. I came to a farm house and knocked on the door. Finally talked to a very old guy who had an old paint can full of decades old spark plugs, all carboned up and very rusty. I grabbed one at random and walked back to the bike. Put the old rusty plug in and she fired right up and I made it home. After that I always carried a spare plug when riding the B50.

One thing I do now in my bikes is never use gasoline with ethanol. Ethanol-free gasoline is readily available where I live, in all three octanes, which is nice.

I doubt ethanol is going to effect the spark plug, some aftermarket fuel additives might however. There are also a lot of copy cat brand spark plugs being made that look identical but last a short space of time.

Gary……..you going to be around on the 25th 26th of this month?? A small group of us will be attending the BIBR at the fairgrounds. We’re going to be camping across the street. Nutley Blue C25, Nice BMW side car outfit, maroon trident…not sure what the others are riding. If you’re going to be there look us up and say hello. Sites 70 and 71.

We can swap tales of failed spark plugs and I’m pretty sure there will be cold adult refreshments available.

Ya gota have spark……..you can live without a lot of other bobs and whistles but you’re not going anywhere without spark.

Gordon

PS…all these years I “thought” I was told to not use resister plugs. ( I have no clue why or if that is even a true statement…my memory sucks). Now since NGK decides to no longer offer non-resister plugs all my riding buddies say they are using resister plugs without a problem. My fix…….stop buying NGK. I’ve had enough of them go bad or be bad out of the box I’m not married to them.

Ran into that when Champs got made in Mexico. NGK & Denso still good and with BB-ign resistor plugs work fine.

Gordon,
I'll come look you up. I'm a member of GABMA and I've been going to British In The Blue Ridge for over 20 years now. I only live about 10 miles east of Hiawassee on 40 acres in the middle of the woods. I'll likely be riding my 68 Triumph Bonneville. My cell is 706-994-5704. Looking forward to exchanging tales. The BIBR rally is really good and they even give away a motorcycle in a drawing. This year it's a 1969 Triumph Bonneville.
Gary

Gary, sounds great. Stop by and say hello. I’ve only attended a few BIBR…. enjoyed them all. We have folks in our group that have been attending the event for decades.

We have several in our group from the Atlanta area. You might recognize some of them. Long time GAMBA members

Triumphs are always welcome. 😊

Owning 40 acres of property in that part of the world sounds like paradise!!!

I’m riding over from Wilkesboro ( 230+ miles one way) and hope to show up before lunch on Friday. My bet is I won’t be the first one of our group to set up. If things go as planned….. I’ll be on an Nutley Blue C25. Hopefully the little bike that could.

See ya…….always great to put a face to a name.

Gordon Gray in NC, USA