COBRA - Snap,Crackle,Pop? PLUG PIC

[Dirtcrasher]

Well I've been running the 87 SX for about a week or so. Definately more power with the Cobra exhaust. I took off the airbox lid to let in some more air as the exhaust is letting more out. The carb is spotless and I set the pilot at recomended 1 1/4 turns out. Idles perfect, starts perfect and runs perfect. But when I let off the exhaust from a good clip it goes - snap crackle pop just like a Harley - trust me it sounds awesome but is it ok?? The plug seem very light tan in color but doesn't seem white. Should I go up a main jet or so?? I have a 350X main jet that screws right in but I believe it's quite a few sizes larger an probably too big. Any suggestions??


Be forewarned though - Cobras run REAL hot!!! So hot you can feel it.

[Honda300ex]

Thats how my 300ex plugs look and its runing just alittle lean. But i wander how did you get that thing to stand on its end?? :? :shock:

[Yamaha_Rules69]

Honda300ex, look a little closer, its in a vice or something. lol

[Russell 350X]

My Big Red does that when you let of the gas, and yes it does sound awsome! My plug looks just like that, but I don't think it is affecting anything.

[hrc200x]

I'm thinking that plug is a little too lean. Another cause of poping exghaust when you let off the gas is from any exghaust leeks you might have. Did you replace the copper crush o ring that goes into the cyclinder? Does it leek around any places where the pipe fits together?

[sand45]

If you get a little back fire is ok! This happens with aftermarket exhausts. Now if it dose it all the time or really loud EVERYTIME you let off the exhaust then you deffinatly running lean. You are gona have to jet up on you main jet at least a couple jet sizes.

[Dirtcrasher]

The main is a 130 on a 250SX Keihin carb, do I just order the next one up? Maybe it's 131?? or 135? Tim Sr had listed a carb web page anyone remember it - it's gotta be cheaper than Honda - oh yeah but they'll have to ship it to. I think the 350X jet I have is like 180 - just a bit big aaye??

I'm betting I gotta go up one size and I'm a tad lean.

Yes it's in a vice I tried to "will it" to stand on end but my brain started to hurt!! - J/K

If plug readings after high speed runs help with the main jet, how do you know the pilot is correctly adjusted and not too lean? Off idle response seems fine, maybe the needle and pilot aren't as critical in terms of engine damage when too lean??

Thanks for your input guys!!

[ATCs Reborn]

you definately should go up a size or 2, you're definately runnin lean, that plug is pretty white. with it that lean you're probably runnin hotter than you should be.
addin a pipe and more intake, you're really only gonna affect the upper rpm's so you don't really need to worry about your pilot.

[atcmatt]

put some muffler putty in front of the header pipe where it bolts onto the head...............mine did it too so i did this and it fixed my problem!! but i dunno if trailprotrailpro problem is the same.

matt

[skippy]

i agree w everyone.. TOO lean... go up !

[yammerhammer]

your plug doesnt look so bad,before you go up one size one the maain raise the needle up one clip.

[Manny55]

i hate how hard 2 strokes r on plugs there not expensive though thank god. That plug looks pretty bad my plug looked like that and it wouldn't start up.