You are looking at the ceramic portion of the plug arent you, not the threads. Reason I ask is that portion will always be black, its the ceramic portion that tells you how your running. Some people dont know that, so I thought I should ask. Also, make sure you get the Keihin jets. We can help you once you get those jets. You have to go up on your pilot as well otherwise your farting in the wind. I promise you, you will be 45 pilot, 168 main, and 3rd clip on the yz needle or 5th on the stock needle. you mixture screw will be 1.5- 2 turns out. That is with the airbox lid off and temps around 70 give or take 15 degrees. If the temp is lower, you will have to jump up on your main jet to a 170. I had to do that yesterday, cause here in Oregon it has dropped to 45-60 degree average temp. Did you check out the Daddog riders site. I learned everything from that site and it helped me to get my jetting right. I already posted the link for you.

 

Well I don't know what to tell you. I think your lean, the jetting that you described as using, sound lean, and yet you insist that you are rich. Anyways, I'm not going to argue with you anymore. Go melt your motor then...

As for melting your motor, Oil only does soo much. If you are running lean (which you are) that means your engine is exposed to extreme temperatures, and allot of your engine is made out of alluminum and magnesium which doesn't necessarily have a really high tolerance for extreme heat. If you run Lean too long and too hard, parts will start failing in your engine, and I will be here to tell you " I told you so"

Good day.

 

This is how I understand running lean (on a 4 stroke) to cause overheating and meltdown. When you unplug that motor (add air) from an airbox mod/filter, pipe, etc, you have to add fuel to compensate for that added air. If you add air without the fuel to burn, that air is heated inside the motor and never burns. So now you have unburned oxygen at high temps going through your motor and that's what will melt your engine. Just for kicks, get yourself that ncvq needle and a pack of jets. A 45 pilot and maybe 165-175 mains. Now start off with the 45 pilot and 175 main and see how it runs. Now downsize one main and see if that's better or worse. Or, if you prefer, do the opposite and start with the 165 main and increase gradually. Try the needle on the 3rd clip to start and keep it there through all of the tests. Now go down on the clip and do it all over again, the same with the fuel screw. Write down exactly what you did and how the quad reacted so you always have a reference point. Another test you can try is to run it throughout the power range with the choke on 1/2 or on fully. Does it run better or worse? With the choke on, you add fuel to the mix. If it runs better with the choke on, you need more fuel. Also pay attentiion to the entire power range when you do this, you may need more fuel mid-range (needle), but maybe not at top end (main jet). Jetting is no exact science. It takes time to understand what you are doing and how those changes affect your bike. Be patient and try all of the combinations. Eventually you will hit the G-spot and make her scream!!!! It sounds like you're getting frustrated, DON'T!! Take your time, do the tests and make the changes until it runs how you want. Good luck.

 

As big as a pain in the butt as the 450 is to jet I hate that part of messing with it. It seems that everyone's jetting is just a bit different from one bike to another. Mine had registered rich everytime I plug checked it. Then I added the header and all the sudden it was lean as all get out and popping on decel. Everyone has their own ideas of what will fix what ails your jetting woes. No exact science to it, just keep experimenting. I finally had to throw the lid back on and im at a 178 main, 48 pilot, 2.5 turns on the screw, and the NCVQ needle on clip4. Im still popping a little on decel and ive heard every answer under the book as to what is causing it, the main, the pilot, the needle, the screw.

It helps to do a plug check in each of the jetting areas so that you are spot on in each area. You want to check the area that the main controls, the area controlled by the needle, and then the area controlled by the pilot. That way you get accurate readings of all the jetting areas. I dont know how you are performing your plug checks. Each jetting area is controled at a certain throttle position. If you were out just putting around for a little while, then pulled the plug it may show for you too be rich but that will only tell you that for the lower end of the throttle area. Ride around at 1.4 throttle for a while so the plug has time to color(pilot jet) . Pull and check it. Then 1/4 to 1/2 throttle(needle position), then get out and run 3rd gear pull the clutch and kill the bike check the plug(main jet). Keep trying you'll figure it out. Might also try. www yfz central com all ran together since atv connection wont let me post their web address, lots of good info on there if you search for it.

 

I feel your pain man, the black plug color sound rich but from what I know the poping sounds lean. I think everyones head pipe glows red so i'm not sure that means anything. I would trash that jet kit, everytime I hear of people using them it just causes problems. Grab some regular jets and start testing. Let us know how it goes. Good Luck!

 

The #1 reason for popping on decel is exhaust leak. You can make it go away by jetting sometimes but it will not run as well.

 

ok ik i said that wuz ganna be my last post but o well, ik it sounds lean the plug says its runnin rich but the poping on deaccel sounds lean so idk wuts goin on, i never used the dyno jet kit i did throw it away i used a regular jet that fmf gives ya, and ever since i put it in the plug has been black but im just ganna buy like 10 differetn jet sizes test all different things out and see wut happends, thanks for all the replies even tho i argued with most of them lol, andyways about the valves not needing adjustment b/c they use shims? wut would that have to do with anything?

 

Just try this and see what happens.
Lid off with aftermarket exhaust.
45 pilot
Stock needle, 4th-5th clip position
170 Main jet
Fuel screw 2 1/2 turns out

Just try that and see if it gets any better.

 

ok thanx but wut if i dont want my air box lid off? wont more crap get into there that way?

 

Yes, more dirt can get in if you remove the lid. Depending on the terrain you ride in, you may or may not want to remove it. Dune riders usually remove the lid. Don't remember if you are a dune rider or not though.

Leaving the lid on will keep you from gaining as much power, but will also keep the air filter cleaner.
With lid on, it will run richer as it is not breathing as easily. You could also cut holes into the lid to allow more air in without letting in too much water or dirt.

If you leave the lid on, try a 165, or a 168 main, with the same other settings and see what happens.