lean and rich????yfz450

[Sturmgiest]

I have a 05 yfz 450, installed a DR.D full race exhuast (no spark arrester no quite-core) Prodesigns pro flow intake w/ foamfilter, and added a 170 main jet, 45 pilot, NCVQ needle (YZ needle) at the 3rd clip

The problem is it's cutting-out/choking at around 1/2 to 3/4 trottle which I figure it ment the main was too rich? so ordered leaner main jets but they're not here yet

The other problem was on the decline it's popping which means it's lean? i'm confused this is my first time working on a carb.

someone please explain what's wrong thanks

[2004exrider]

im not a carb expert by far but ill try and help ya as much as i can.
pilot controls 1/8 to 1/4 throttle, needle controls 1/4 to 3/4, main controls 3/4 to full. so id say that you need to raise your needle up a clip to lean it out. for the popping try adjusting your idle to what your owners manual says.that should help it out.

Jimmy

[greg_gorrell]

well cant be be both.....posy a pic of you spark plug or tell us what color it is.

[ss440ex]

Raise your needle and turn the idle mixure screw out
1/2 a turn at a time for the decline popping.
Should help.

[Sturmgiest]

the ceramic part of the plug is white but the end where the spark gap is at is black

[TRXRacer1]

Originally posted by Sturmgiest
The problem is it's cutting-out/choking at around 1/2 to 3/4 trottle
^^^ LEAN

[bwamos]

Aye all the symptoms are lean on the 1/2-3/4.

Move the needle up 1 position. (Clip down 1 notch)

Should fix the cutting out problem.

After that mess with the air screw to get rid of the popping during deceleration.

ss440ex was right on the mark.

Also plug checks.. you check the ceramic insulator for color.. not the tip. ;) But you cant really doa plug check unless you run it at that rpm for 30seconds (under load), and pop the kill switch.. keeping throttle in same position until the engine/quad stops. Dont let off the throttle or you can get a false lean reading.