need some jetting advice

[coltrain65]

i have a 2007 trx 450r electric start
It got an AC Flow full exaust, and i am running the stock air filter and i left the lid on.
wondering what kinda main i should go with i currently have a 140 main, stock needle and fuel screw, and a 55 pilot. wondering what all i should changed i how much i should change it i am in missouri i believe around 1200 ft above sea level. also does anyone know where i can get an aftermarket needle, and wheres the fuel screw located in the carb?

thanks in advance.

[DnB_racing]

your spark plug will tell you a lot about how your quad is running and also check for a puff of black smoke when you start, I like to see a little puff of black smoke then bring the main down to just were it stops that ensures its not running to lean. your A/F screw is on the bottom towards the front and needs a special tool. SUDCO specializes in fcr carbs they have everything you need for the carb and have good tech support to answer questions on exact settings

[450rdr424]

as far as main jet try between a 158-162 that should get you in the ball park, check your plug and get back to us with the color of it i like my plug to look like chocolate milk in color

[DnB_racing]

here is a little explanition on altitude and temp jetting its a little long but worth reading : first example let's say we find a new riding area WAY up in the mountains. Our jetting is dialed in for our usual riding area which ranges from sea level to 1500 feet. Our NEW riding area starts at 4000 feet and goes up from there. Going to a higher elevation will require will require a jetting change but which way? Like our fuel density, air density can also change. Higher elevations have less air density then lower ones. At high elevations our engines are getting less air, so they need less fuel to maintain the proper air/fuel ratio. Generally you would go down one main jet size for every 1750 to 2000 feet of elevation you go up (info for Mikuni carbs). If you normally run a 160 main jet at sea level you would drop down to a 140 at 4000 feet. Something else goes down as you go up in elevation is horsepower. You can figure on losing about 3% or your power for every 1000 feet you go up. At 4000 feet your power will be down about 12%-even though you rejetted! For our second example let's say we are still at our new 4000-feet elevation riding area and a storm comes in. We head back to camp and ride it out overnight. The next day there's a foot of snow on the ground the skies are clear and it's COLD! Aside from getting the campfire going and making some coffee you should be thinking about jetting again! Cold air is dense air and dense air requires bigger jets. If the 140 jet ran good the day before you will need a bigger jet to run properly today. If the temperature is 50 degrees colder than it was the day before you can actually go back to your sea level jetting, a 160 main jet! If you don't rejet you can kiss your assets goodbye when you rebuild the seized engine. Air temperature makes that much difference!http://quadhub.com/extras.php?location=Jetting%20Calculatorhttp://quadhub.com/wiki/index.php?title=Jetting_theory