spark plugs

dezwartj said:

I used the NGK 89ES for the longest time but due to my apparent non-skill in tuning the carburators properly I had to clean the plugs every 200 miles of riding (way too rich)

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B9ES?

B9ES plugs would be two heat ranges too cold, so they would likely have sooted up because of that.

Setting up the carburetor (Amal) might eliminate a lot of this spark plug chater! :roll:
http://tinyurl.com/29r2h4w

Should do, Bob. You're triggering off of the plug current after all, although the time jitter may be too large to see the effect. The rise time of the plug voltage, and the actual firing point along that voltage curve is assumed to be instantaneous. Variations are usually quite small, but 30% increases in gap size, or large reductions in firing voltage, are a different story.

When is a resistor plug required? Running sparx electronic ignition, currently using NGK BPR7ES...

Cheers,

- HJ

Joe,

You need to provide some form of resistive ballast in the spark path, about 5 kOhms, if you're using IE and/or an electonic regulator. If you're happy with your conventional plugs, NGK makes an attractive resistive cap for a few bucks. If you decide on exotic plugs (iridium, platinum) they are all resistive, and you will need to use a non-resistive cap, or one that provides less than 1 kOhm of resistance. A DC ohmmeter tells you everything you need to know about the system resistance.

R or Non-R plugs are determined by the type of ignition system and courtesy to others with radio wave sensitive devices. Coil flux collapse and rebound rings in coil and the wires connected and can back feed into solid state brains or make points arc and pit. I've run both on analog Boyer w/o and issue but angry looks of drivers and syncopated timing light LED turns signals. In Ms Peel's deal I had spare audio 5 amp power filter inline with its fuse to keep its beat pure. Some ignitions may need the resistance for voltage rise to fire in time, don't really know.

Hungry J0e said:

When is a resistor plug required? Running sparx electronic ignition, currently using NGK BPR7ES...

Cheers,

- HJ

Click to expand...

As stated, with electronic ignition you need either resistor wires, resistor caps or resistor plugs. But not more than one at a time.

I prefer resistor plugs because resistors occasionally fail and with the resistors in the plugs you get new ones each time you put in new plugs.

You can run helical wound resistor wire with a resistor plug for best radio suppression. Helical resistor wire is very low resistance. 2 to 5 hundred ohms per ft.

Running carbon core resistor wire on a Norton is not a very good idea as the vibration causes the carbon core to fail over time.

The shift in timing with realistic changes in secondary resistance or plug gap is very small. Not usually a concern. Jim

There are 2 main types of electronic Ignition, Analogue and Digital. The Boyer black box is analogue and the red and blue are digital. Analogue do not need a resistance in the coil wire or plug but Digital do need a resistance.

And many voltage regulators require resistance in the secondary circuit.

OK, I run a black box, and I have 5K resistor HT wires, for no other reason than they were already on the bike when I got it, and I never changed them. Not knowing or thinking platinum plugs are additionally in and of themselves resistant, I've been running the bike like this for a season. I like the platinum plugs because they don't foul, and I don't mind, and would actually prefer, if my bike runs a little rich. It's not that bad really, as the plugs really keep clean. What is the real risk to running these plugs alongside the resistor wires? I can see it might be harder starting and running, possibly exacerbating an overly rich setting due to incomplete fuel burn. Is this the issue, or is it something more sinister? My bike seems to run fine, BTW.

No danger, just the possibility of harder start or missfires due to the higher voltage requirement to fire the plug.

If you are running a single coil then you must use double platinum plugs or you will only be getting the benefit of platinum on one cylinder. That would be the cylinder that happens to be connected to the positive tower of the coil. The plug connected to the negative tower will act the same as a standard plug. Jim

If you are running a single coil then you must use double platinum plugs or you will only be getting the benefit of platinum on one cylinder. That would be the cylinder that happens to be connected to the positive tower of the coil. The plug connected to the negative tower will act the same as a standard plug. Jim

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Interesing there.....the one cylinder does appear to blacken the plug more than the other. I changed to a dynacoil last year. Damn, back to the drawing board.

Jim, does the same thing go on with individual coils wired in series?

bpatton said:

does the same thing go on with individual coils wired in series?

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No.

Been over this part before, ie: two different polarity/electron spark directions on either plug. Electrons jump off sharper peaks easier than rounder/flatter surfaces, so it both takes more voltage rise to jump the reversed polarity plug ie: hook towards center post than visa versa. Studies have been done on this by a few different ways to find up 15% less spark or power gotten out of the reversed flow plug. Only solution is hot enough ignition its a moot issue or stick with dual separate spark ignition. Solid state "dual spark" systems cost most so their sales pitch is better starts and idle and smoother running over all and a dash more peak power. All aftermarket common Norton ignitions are "wasted Spark".

This the reason coils had terminals polarity marked. Distributors acted like our old points to fire only one plug the best way. Old method to check coil or plug polarity was to stick pencil lead in current path and see if it blasted off incandescent carbon brightness sharp or fanned. Maybe another reason points seem to have more response kick to em, gave best spark polarity in each jug.

Here's Steam and hit/miss engine site short review on checking polarity.
http://www.smokstak.com/forum/showthread.php?t=82256

A spark plug is a spark plug, sounds obvious but thanks to advertising etc. the subject has got confused. Plugs are rated on the heat range. Check to see what the correct heat range/plug make and number you should be using. Champion have been making plugs before most of the "Splitfires" of the world were born! The most innovative technical advance Champion has made is their thin platinum center electrodes (suffix G, N3G etc.), these are less prone to fouling. What determines how the spark plug performs is the power available to produce the spark. Most modern transistorized ignitions can provide adequate power for your bike. I raced a highly tuned Norton for years on total loss, points ignition using various heat ranges of Champion plugs with no fouling or ignition problems. Bear in mind this was with an engine reving to 7000. Most "problems" people have with spark plugs have other causes: poor carburation, low voltage in ignition circuit, slipped timing, poor oil control in the engine etc, etc.