Spark plugs

387 Views 3 Replies 3 Participants Last post by Jerseyboi94, 3 mo ago

Jerseyboi94

Discussion Starter · 3 mo ago

So I have a concern can you tell if engine is Rich or lean as you can see the plug on the left is what it looked like before new air filter & manual choke..the plug on the Right is what it looked like after parts & riding around a few times

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SoakedKarma

· #2 · 3 mo ago

To properly read spark plugs engine needs a good highway run.
engine is cut off, coast to side of road and pull plugs without allowing any idle time..

Spark Plug Reading 101 by Mike Canter - Dragstuff

In depth article on how to read spark plugs - learn about how to read air / fuel mixture, timing and other tell-tale signs for optimum performance.

www.dragstuff.com

check the additional links at bottom of page

I don't hold a lot of stock in reading plugs unless they are carbon or oil fouled.
Can't remember the last time I looked at insulator fire ring discoloration, but remember that it was good when checked..

Spark Plug Reading 101: Don’t Leave HP On The Table!

If you’re not paying attention to the most important step in the four-stroke—the point of ignition—you’re leaving horsepower on the table.

www.motortrend.com

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BigBob

· #3 · 3 mo ago

I have never been a believer in "plug chops". I check plugs after they have at least a couple hundred highway miles on them. Don't check them right after using the choke. In your picture, the top plug shows too lean, but if it is new it may change with some miles. The plug on the bottom shows too rich, but again, if it was removed right after running the engine with the choke on for several minutes, that will not be accurate. If the air fuel mixture is correct, the insulator should be a dark brown, but not black. Also, if an engine is burning oil, it will be impossible to get an accurate reading from the plug, because it will be oil fouled.

When you say new air filter, do you mean a new stock air filter in the stock airbox, or something like a pod filter? Getting rid of the airbox and installing a pod filter will seriously lean out the air/fuel mixture. Are both plugs the same number? Plugs with a different heat will also cause inaccurate readings.

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Jerseyboi94

Discussion Starter · #4 · 3 mo ago

BigBob said:
I have never been a believer in "plug chops". I check plugs after they have at least a couple hundred highway miles on them. Don't check them right after using the choke. In your picture, the top plug shows too lean, but if it is new it may change with some miles. The plug on the bottom shows too rich, but again, if it was removed right after running the engine with the choke on for several minutes, that will not be accurate. If the air fuel mixture is correct, the insulator should be a dark brown, but not black. Also, if an engine is burning oil, it will be impossible to get an accurate reading from the plug, because it will be oil fouled.

When you say new air filter, do you mean a new stock air filter in the stock airbox, or something like a pod filter? Getting rid of the airbox and installing a pod filter will seriously lean out the air/fuel mixture. Are both plugs the same number? Plugs with a different heat will also cause inaccurate readings.

The one on the Right is still new only a few miles on it not a lot..& it's a new stock air filter.. I also don't use the choke to start it..it electric starts just fine

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Spark plugs

Jerseyboi94

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Spark Plug Reading 101 by Mike Canter - Dragstuff

Spark Plug Reading 101: Don’t Leave HP On The Table!

BigBob

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