i checked my plugs and my ground strap was a white/grey color and the base ring was a light brown color. i have read that u use the base ring color to determine your jetting. if this is so, my jetting is correct? i should add my headers glow red at night. bright red if i putt around and not so bright if i give it alot. i should also add, i just changed my plugs with proper gap, and torque. before i changed, my plugs had a dark brown ground strap and and black base ring with proper gap and torque.

 

Some people are gonna tell you that you're running lean but IMO you're burning perfect now. With the additives in today's fuels it's hard to read plugs to determine jetting, and most of the time it's better to go by the color of the exhaust tip. Plus most people don't understand that a 4 stroke motor isn't running lean if the plug is a light color. There are some people on here that have taken there quad to a dyno to get jetting spot on and they were very surprised to find after they found the jetting that gave them the most power the plugs were gray in color. So again I think your jetting is fine, but the probability that many people will disagree with me is high..

 

so if a white/grey color ground strap is not too lean, how do i know when i have a dangerously lean condition?

 

I've heard of the glowing header thing, and personally never seen it. To me, its the sign of a lean bike and would cause me sick concern.

To me plugs are really hard to read. In order for me to trust a plug, I have to drop in a fresh plug when the motor is warm so I don't use the choke. The plug goes in right when the next moment of life is about reading a plug. Then I do a full speed run, idle to 7,000 rpm. No putzing around the pit looking cool, just a speed run. At 7,000 hit the kill switch and pull in the clutch and coast to a stop. Pop the plug and read it.

As this is to much trouble, I don't read plugs anymore. I use a stop watch over a measured distance to establish performance increases or decreases. I've seen countless bikes feel "snappier" with a jet change, yet log 2 seconds slower in the quarter mile.

I check plugs out of curiousity, not so much as being smart enough to know what its trying to tell me.

jbt

 

If the electrode is white then I guess you could jet up to feel safe but I have seen many 4 stroke motors leaned out to the nuts and run just fine without no problems. My cousin's YZ440F motor is a perfect example. After he got the motor bored and stroked from a 400 to a 440, he didn't rejet it and it ran SUPER SUPER lean all summer in 80+ degree temperatures without any problems at all. I tell you it was SO lean that the exhaust tip was WHITER than a piece of clean printer paper! Now I scratched my head all last summer why he ran it like that, but I guess he was just too lazy to re jet the dam thing. I tell you it ran DAM good too, but he finally got around to rejetting the carb and it runs a bit better but I'm sure he didn't jet up much at all! That was proof to me on how far you can lean out a 4 stroke motor without worrying if you're gonna burn it up. By seeing that and many other 4 stroke motors run like that it changed how I think about what's lean and what's not, so IMO you are not even close to running lean and having to worry. But again, 99% of the people arn't gonna agree with me no matter what I say.

 

my friend has a yfz 450 and yz450 both are stock carb and jetting. he has a fmf exhaust that came with a intake filter for the bike. he pulled the pee shooter and spark arester out of the yfz. they both have glowing red head pipes at night. I told him he should rejet to at least one or two sizes bigger on the main jet. not sure what to tell him now.

 

Pushin'

I have seen my bikes run fast as the wind on the flats, yet fall flat on their face in the sand. This is a good example of "fun running lean tuning". I prefer to tune a bike under a load (prefer uphill, in the sand) traversing a measured distance in a noted timeframe. Two flags and a stopwatch is all that is needed.

If your not near any sand or hills, use fifth gear over a quarter mile, it will show improper tuning on the top end.

Being a financially strapped individual, I run my 4 quads slightly fat so I don't wrench on them all the time. I would rather spend cash on making my bike going faster versus trying to fix my kids blown motor that only lasted 3 years instead of 10.

The fact a manufacter has engineered a vehicle to survive a lean condition over a period of time does not impress me. As your luck appears to mirror mine, I figured you would understand.

jbt

 

No you're getting me all wrong here. I don't want anyone to run their quad that lean. This is just what I've seen and all I'm saying is there's A LOT of room for "lean jetting error" and "spot on" jetting is a little leaner than what most people think.

 

I'm reading what you throwing down. Its just hard for folks to articulate what is trying to be said via a stupid keyboard. But, I'll live with the problems of emailish communications versus not talking quads at all.

You are absolutely correct, a lot of folks confuse a lean condition with proper jetting.

Regards,

jbt

 

The leaner, The meaner!!!!!!!!






03 kfx 463cc from 4-stroke tech, port & polished, 3 angle valve job
39mm keihn carb, dyna-tek ignition box,K & N pro design, custom heel guards
ac nerfs,lsr +2 a-arms, lsr+1 swingarm, +4 durablue axle,ITP baja wheels with Holeshots
heavy duty clutch and valve springs,Tag bars, Ez pull clutch, red mair plastic,pro armor bumper, CT full pipe
deciding if alky or nos is the next step?