What does this plug tell you
Discussion
Your picture suggests your engine is running normally and the air/fuel mixture is correct. This is the correct colour a spark plug should be and it tells the PH'r everything is fine with the engine. A carefully trained 8 year old would install a new properly gapped plug. When installing a new plug, replace the old one with the same heat range. A new plug would have square edges that helps the plug fire better.
On a cautionary note, it's a slightly black dry fluffy coloured plug which suggests deposits from a carburettor that is running too rich (too much right foot?), or excessive idling on some engines. Black smoke coming from the exhaust is a sign of a rich air/fuel mixture. The rich air/fuel mixture must be repaired before installing a new spark plug. Common causes for a rich air/fuel mixture are:
dirty air filter.
air mixture screw or carburettor needs adjusting.
choke is sticking.
carburettor float height is out of adjustment or float is sticking open.
Clean your thingy.
On a cautionary note, it's a slightly black dry fluffy coloured plug which suggests deposits from a carburettor that is running too rich (too much right foot?), or excessive idling on some engines. Black smoke coming from the exhaust is a sign of a rich air/fuel mixture. The rich air/fuel mixture must be repaired before installing a new spark plug. Common causes for a rich air/fuel mixture are:
dirty air filter.
air mixture screw or carburettor needs adjusting.
choke is sticking.
carburettor float height is out of adjustment or float is sticking open.
Clean your thingy.
Scruffy said:
Your picture suggests your engine is running normally and the air/fuel mixture is correct. This is the correct colour a spark plug should be...
Then...
scruffy said:
On a cautionary note, it's a slightly black dry fluffy coloured plug which suggests deposits from a carburettor that is running too rich (too much right foot?), or excessive idling on some engines.
Make up your mind, Scruff!
I'd say it looks like the engine has been running a bit rich, personally. It certainly is not the right colour if the air/fuel mixture is correct - that would result in uniform light brown deposits on the plug nose, not crusty black ones!
If it's from a Griffith, it is fairly unlikely to be a carburettor problem.
Finally...
scruffy said:
Clean your thingy.
I find this sort of remark a bit personal for a public forum. The state of Banana's thingy is none of your concern!
hew: took me how many hours since first one
no more pics please I hate to be controversial, but I'd say hot and/or lean. Rich is very black indeed, and dry the deposits are soft and dusty.
Normal to lean is grey, lean is usually hot, and hot causes the electrode to decompose, which yours appear to be starting to do.
Maybe, the plugs aren't the right temperature rating.
I found some pictures from the web, so you can judge for yourself;
www.nightrider.com/biketech/spkplghnbook.htm#We
>> Edited by dilbert on Tuesday 19th April 22:36
Normal to lean is grey, lean is usually hot, and hot causes the electrode to decompose, which yours appear to be starting to do.
Maybe, the plugs aren't the right temperature rating.
I found some pictures from the web, so you can judge for yourself;
www.nightrider.com/biketech/spkplghnbook.htm#We
>> Edited by dilbert on Tuesday 19th April 22:36
That's not far from being OK .... looks like short journey work.
If anything I would say a little rich, but that would also tie in with the comments about short journeys.
If it was lean I would expect less deposits ... burnt off by heat, but unless you are using the engine for a little mileage allowing the engine to come up to normal operating temp for a while they won't ever look right.
More runs like we had to Donington
If anything I would say a little rich, but that would also tie in with the comments about short journeys.
If it was lean I would expect less deposits ... burnt off by heat, but unless you are using the engine for a little mileage allowing the engine to come up to normal operating temp for a while they won't ever look right.
More runs like we had to Donington
I always thought the colour of the electrodes was paramount - there's bound to be some variation over the whole of the plug including the threaded collar. I wouldn't worry that the collar's blacker than the electrodes. The electrodes look fine to me. In general I understand most Griffs run a bit rich. Wheeler never got around to developing lean-burn technology I guess...
It's unlikely all plugs on the same engine will look the same - the fuel rate per cylinder should be roughly equal between cylinders, but due to the design of the inlet manifold and plenum the air flow won't be. As such air/fuel is a best fit for the average of all cylinders and therefore likely not to be ideal for any one. My Adams-tuned precat runs a bit rich if anything. Rather that than burn a hole in a piston I guess...
It's unlikely all plugs on the same engine will look the same - the fuel rate per cylinder should be roughly equal between cylinders, but due to the design of the inlet manifold and plenum the air flow won't be. As such air/fuel is a best fit for the average of all cylinders and therefore likely not to be ideal for any one. My Adams-tuned precat runs a bit rich if anything. Rather that than burn a hole in a piston I guess...
griffter said:
I always thought the colour of the electrodes was paramount - there's bound to be some variation over the whole of the plug including the threaded collar. I wouldn't worry that the collar's blacker than the electrodes. The electrodes look fine to me. In general I understand most Griffs run a bit rich. Wheeler never got around to developing lean-burn technology I guess...
It's unlikely all plugs on the same engine will look the same - the fuel rate per cylinder should be roughly equal between cylinders, but due to the design of the inlet manifold and plenum the air flow won't be. As such air/fuel is a best fit for the average of all cylinders and therefore likely not to be ideal for any one. My Adams-tuned precat runs a bit rich if anything. Rather that than burn a hole in a piston I guess...
Best to run rich than lean
you wana see my flames 
Ste.
stesrg said:
I always thought the colour of the electrodes was paramount - there's bound to be some variation over the whole of the plug including the threaded collar. I wouldn't worry that the collar's blacker than the electrodes. The electrodes look fine to me. In general I understand most Griffs run a bit rich. Wheeler never got around to developing lean-burn technology I guess...
It's unlikely all plugs on the same engine will look the same - the fuel rate per cylinder should be roughly equal between cylinders, but due to the design of the inlet manifold and plenum the air flow won't be. As such air/fuel is a best fit for the average of all cylinders and therefore likely not to be ideal for any one. My Adams-tuned precat runs a bit rich if anything. Rather that than burn a hole in a piston I guess...
Best to run rich than lean
Ste.
mines popping and banging even more than normal know
BB
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