2004 yfz 450 carb problems i thank

i just bought a 2004 yfz 450 and noticed the exhaust is glowing red hot from the head down the pipe about 8in is that good and how can i fix it  

sounds like your atv is running a little lean at the fuel/air mixture screw. try 1/4-1/2 turn to the left on the fuel/air mixture screw.

if it persists or gets worse then you may have a post ignition problem due to excess fuel entering the hot exhaust and igniting.

try tuirning the fuel/air mixture screw first.

you do have a stock carb on it right?  some performance carbs are the opposite, depending on whether the air/fuel mixture screw is located upstream of the throttle valve (slide) or downstream.  upstream and turning it clockwise gets you richer, ..downstream and you have to turn it counterclockwise to get richer. most stock carbs are downstream.  
Keep it RUBBER SIDE DOWN!!

Hi i am new to this cite and thought i had a nice running quad till i got done reading.. it fals flat right off idle even when warmed up its new stock i just changed the filter "uni filter no kit" i tried puting a pipe on DG xccelarator 3 and dg suggests a larger main one size up so i put a 165 in and started it about 1 min later the pipe was almost see through i almost found gold bricks in my britches i thought greeat this is going to blow so i shut it off and tossed a fan infront of the head pipe. i called dg and they said its a free flow exhaust and they will glow so i just hung up i've been there done that i did tell him that it was after one min and he tried to stick with his story so i figured like you stated in responce earlier to the other post its lean. i did take it off and put factory back on to ride and it runs fine except that it fals on its face or cuts out i mean some times if i hit it off bottom even when warm. top end its good.  could you walk me through how to get this pipe done i don't know how long to run it to cheeck the plug correctly and were the mix screw is "in bowl out side the carb" on bottom i sure could use help and know how to turn a wrench just not tuning anything... thanks..  

first place to start is with the plug chop, the plug color will tell you what you need to know.

i'd put the rich jet in 165 and then work with the fuel/mixture screw.

also remove the airbox lid see if it gets better or worse.

the fuel mixture screw is on the bottom of the carb under a cap.  
Keep it RUBBER SIDE DOWN!!

ok first thank you. now Question one how long should i let it run before i do the plug chop. second should i use a new plug if so everytime or use the same one. and can idle be a based to start and do i need to run it down the road to have a load or can i rev it to do a chop? do i worry about the red glowing pipe in the mean time? . .And again thank you, i apreteate your time and help!  

warm the engine so that it isn;t cutting out because the engine it cold.

throttle chop, ride it in high gear holding throttle wide open for a little ways and then while you are holding the throttle wide open hit the kill switch and come to a stop.(don't let off the throttle until you come to a complete stop and hold the clutch in after killing engine) check the plug. white too lean , brown or black too rich, creamy tan color just right!!!

then do an idle chop, let it idle after the engine is warmed for a few minutes and kill the engine. check plug color.

pilot jet controls idle, main jet controls throttle.

all of the suppliers of atv mods think everyone who buys them is an expert on tuning.
so they don't go into detail.

don't just rev the engine at idle, it wont be under load and you wont get an accurate reading.

running  a short period for plug chops shouldn't hurt the engine. just don't go more than a minute or two for each chop, and let it cool down between them.

main thing you are worried about is pre-ignition due to your fuel mixture being too lean.

always a good idea to run a jet larger than you think you'll need and work your way smaller, to reduce the risk of damaging the engine.
the dg may glow a little, but usually you won't see it until after dark.

if you are seeing it during daytime in the sunlight, then you definately don't have it tuned right.  
Keep it RUBBER SIDE DOWN!!

OK thank you great discription i will do this, i will put the DG pipe on tonight put the larger main in and one up the pilot to make sure also and run your discription in thee morning.  

Ok i took a look at it today which was a mericle in it's self as I am a full time college student and contrary to most people's beleifes i don't get much free time... any way I put the pipe system on and turned the carb side ways to find that there are three under cap on bottom so iasume one is pilot middle is main and on either side of the main jet is the mix screw i am not sure which is which im on stator side not clutch with carb bottom tilted toward me and they look pretty similar both have screw heads the only one i am sure of is the main cause it looks like a usual main.  I have a 04 blaster as well and am use to the mis screw being on out side could you or someone please let me know which is which? Thanks oh yeh i apretiate you offering hlep it's nice to have these forums i might need help come winter when i do a total rebuild on the blaster motor. That one is cheaper to fix so i dont mind taking more chances LOL thanks guy's .... Ride on..  

got it