400ex 450r Carb jetting?

[xX-Clutch-Xx]

I got my 450r carb on, and it idles decent, Doesnt stall when warm, But when you give it gas yes it revs quick and hard but it backfires a bit and pops blue flash flames out of the pipe. All mods in my sig. So far i have a 160 main (dynojet) stock 48 pilot, air fuel screw 2.75 turns out, And it crackles and pops bad when its calming down and then it stalls if i drop the throttle. If i do it slow it doesnt stall so much. Any jetting/ Tuning references would be good. I started it and revved it a bit last night and checked the plug today and it was beginning to turn white so i went from 155 to 160 main

[CJM]

If your using dyno jets I cant help ya, they wont ever allow you to jet the carb right anyways.

You need a 50-52 pilot and a 168 or so keihin jet. Your local shop should have them or try www.jetsrus.com

[xX-Clutch-Xx]

Also i have the needle on 3rd from the top. I might order some jets too since they are cheap. But im still gonna work with my dynojet a bit. Ive never had issues with them. and what about the fuel air screw?

[CJM]

3rd notch from flatend, 2.5 turns out is where Id start. Your gonna need the larger pilot jet tho.

[xX-Clutch-Xx]

I ordered a 50 and 52 pilots, and few mains 168 and up. The main response is actually decent but its the idle and imediate bog when I pump the throttle.

[JOHNDOE83]

those usually are signs of being lean, what did you use to plug your hotstart?

[xX-Clutch-Xx]

I broke the cable holder at the threaded part so its like a screw/plug. i might get a bolt to put there but it seems to be a good seal
-

[JOHNDOE83]

Pluging the hole does work but you have to seal the tiny hole in the carb port also, if you go that route. Mine is sealed with RTV and works great even tho other members swear it will never work, mine runs 5's in 300ft dirt drags smokin banshee's and 450's, so it must work really well.

The hole in the carb port is on the topside, inside the carb just underneath where the hotstart is.

I would seal off your hotstart the proper way before trying to tune anymore, either seal it like the other hotstart users did, or try to use the bolt "with sealer" and pluging the other hole also.