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Spark Plug Picture: Rich, Lean?

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to me this looks like its running rich and is a little fouled...

however the way the bike is running and carb jetting indicates its a bit lean...

wanted to see what you all think, thanks

2011-11-27161628.jpg

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honestly, jetting by plugs are not the way to go, i go by feel, how does it run, does it idle good, does it start good, does it start when hot good with the hot start, does it bog when you whack the throttle etc, does the choke work good, etc etc

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not zoomed in far enough.

and perfect jetting gets the plug looking the same coming out as it went in brand new.

and no plug will look like new even if your bike is jetted correctly, what do you mean by this you have to be more specific

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I'm not exactly sure if this applies to four strokes, but for two strokes it should look the same color as a toasted marshmallow.

Also remember that it doesn't help much if you idle roll up to where you're going to work on it and then pull the plug. You should run it under load in whatever throttle range you want to test the jetting, then at the same time pull the clutch and kill the engine. Then pull the plug and check the color.

I've heard people say that the plug chop test is useless for four strokes though, so IDK.

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yes for the most part a plug chop test is worthless on a 4banger. overtime it will show the true nature of all of the circuits of a carb.

but a clean burning combustion chamber will leave nothing on the plug. it will look brand new.

using pump swill will NEVER produce this.

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yeah this is after a few months of use...

im not jetting based on the plug but via other methods (obviously not a dyno)

just curious...bike exhibits signs of both lean and rich, since the places i ride vary in temp/elevation A LOT (sea level 70s-80s to 30s-40s 8K feet)

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its not a close enough pic to know.

but that kind of elevation and temp changes is to vast without jetting changes for each.

that is where closed loop efi works. open loop efi wont be any better than a carb.

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believe me, id love to have an EFI bike, but its not in the cards yet....

yeah, i expect to re-jet for those elevation changes too, but what kills me are my buddies with yz's and some crfs that dont re-jet and they are running perfectly fine in the same places..

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then you are currently setup for 1 end of the range. you need to jet for the middle elev/temp and then it wont be so bad on either extreme.

if you have a yz send me a pm and i'll work with you on it.

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