dead spot

[yfz113]

I have a stock 07 YFZ 450 and ther is a dead spot in the throttle what can i do to fix it I have heard that a accelerator pump will help but im not too sure

[TWILES]

Where's the dead spot?

[yfz113]

right when you get on it hard it has a delay

[the*ovenman]

I have an 06 that does the same thing and from what I have read its a very common occurence. What I have done to try and correct this is I got a Stealth racing Technologies Accelerator pump cover and when I put my Exhaust on I changed out the Jets. I got a Dyno Jet kit It came with the needle and an assotrment of main jets and one Pilot Jet. I just installed it all last weekend and am going to the desert this weekend and will report back on monday if it helped at all. I also installed the Prodesign flow kit w/ K&N filter.
I used the CJ165 Jet and put the clip on the needle at the 3rd notch from the top and 1.5 Turns out on the fule screw. I basically followed the directions that came with the Jet kit. This is my first experience with this kind of stuff. When I get back I will let you know how it worked out.

[YFZ450Ridr]

from all that i have read, on these bikes you can not stab the throttle. you have to somewhat roll into it. somthing to do with the accelerator pump. i have heard a Boyesen quickshot 2 helps with it but i dont have first hand experience. ive been contemplating picking one up for a little bit. they say it gets rid of the air that is in the accelerator pump and keeps it always full of fuel reducing the bog.

[bradley300]

you dont need to buy anything but jets. i run a stock air filter, no lid, HMF slip on and my jetting is 45 pilot, NDSR needle #3 down, 170 main, 30 leak jet and 2 turns out on the air screw.

mine has a very slight stumble when you stab the throttle now, but i think a 25 leak jet will cure it.

the leak jet is causing the problem but is hard diagnose until the pilot and air screw are correct. turn the air scre 2 turns out and start changing pilots until it runs its best. once you have that figured out, you can start changing leak jets and see results

one thing o havent done is adjust the accelerator pump. but i heard you can take off the throttle housing on the carb and see where the throotle arm activates the a/p and you can mess around and get it to activate sooner.

[TWILES]

I have an 05 WR450 and the motors are really close. I took the smog stuff off and played with the accelerator pump and got it taken care of. If you want to set you AC pump to where mine is, turn the screw untill its as far up and the pin will go and leave it. It gives it a better squirt. The bottom 1/4 throttle is touchy all the time. I just blip the gas to get it off idle before I hammer it.