450r carb help

[bcleveland]

Hey guys need some more help getting this ride rolling again. OK here is what I have. Its a 07 400ex stock bore 12-1 JE piston. Head has been mildly ported. Running a stage 1 Hot Cam. Stock head pipe that has had the welds removed and smoothed out. Big Gun slip on. And a 05 450r carb with K@N filter and open top aluminum airbox. I have been working on jetting the last couple days and darn its giving me fits. Yesterday had it running pretty good with a 48 pilot and a 160 main, needle on the 3rd from the top notch. I was running factory tires and was having a blast drifting the rears are very slick. My neighbor brought me a set of new Kenda Klaw MXers. It went to crap then. I know I am running fat on the bottom its huffing black smoke at idle and on launch and the fuel screw is only a 1/2 round out. But when I launch with the new tires or hammer it coming out of a turn and put a hard load on it that pulls the motor it cuts out and tries to die. So should I try something like a 46 pilot and a 150 main?

[JOHNDOE83]

Try going 2.5 turns out and see if it still dies like that.

or have you done that already?

If youve done that already try the 46 pilot without changing the main jet.

[bcleveland]

Yeah I tried that loads up bad on the bottom and will start sputtering at about 1/4 throttle just trying to take off.

[JOHNDOE83]

Ya deff go smaller on the pilot jet then, as long as the topend fully revs out, the 160 main wont be to rich and 3rd notch on the needle seems to be the best spot for many diff builds and mods.

[bcleveland]

Ok sounds like thats the new plan. Also I was on I think its jetsrus whatever the company is in the sticky section. They have keihin jets and then oem equivelant that are a good bit cheaper especially in the mains. Would it be ok to use those or just suck it up and spend the extra money on the keihin jets?

[JOHNDOE83]

Oem equivalent is fine, I buy all my stuff from jetsrus also, Ive bought standard oem and oem equivalents, Id buy equivs if I were you.

Saving a few bucks is always good....:D

[hondaREX]

Did you get the 450r carb used? I just got through a headache with my 450r carb. It was acting about the same as yours. I had to clean the accelerator pump and the 2 ports that are under the accel pump. The ports are very small and there are these square "plugs" in the upper part of the ports. I had to clean around the squares with a single bristle from a wire brush and soak with carb cleaner and blow them out with air. If you were to have the bowl off with a little fuel in the bowl, and you push the accel pump shaft down there should be fuel that comes out of the square ports. Thats all that was going on with mine. Used carb 101: disassemble EVERYTHING and clean the crap out of it!! Your problem may be the pilot circuit but i figured id share my fix.