2000 Yamaha WR400 wont run with choke off.

SOURCE: 2003 yzf450 wont run right?

recheck pilot jet & pilot circuit.also check compression

SOURCE: Will not run without choke

have you checked for vaccuum leaks at the intake manifold? you can check by pouring water over the gasket area when/ if you get it running!

SOURCE: Won't idle without choke

The pilot jet controls the air/gas fuel mix at idle . If the jet gets plugged up not enough gas gets to the emgine at idle. You will need to remove the carbs and float bowls and clean them, paying special attention to the pilot valve. Count the number of turns to remove the pilot screw and replace the same number of turns then turn counter clockwise 1/2 turn.

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SOURCE: yamaha 125 grizzly starts and idles when choked but dies when acc

Take the carburetor apart again, remove the main and idle jets and idle mix screw, plus the float and needle valve. The main jet holds an 'emulsion tube' in--look inside where the slide valve moves, you should see a short brass tube projecting out of the bottom. Carefully push down on that tube with a plastic rod or wooden dowel, it should drop out the hole where the main jet was. Chances are that the tube is dirty and needs to be cleaned--look carefully at the series of small holes drilled into the sides of the tube. These small holes deliver air which is mixed into the fuel passed through the main jet. That air comes from a small hole just inside the intake side of the carburetor. The long needle that sticks out of the slide bottom controls low to mid-range speed fuel-mixture. Check that the 'C' clip on the top end of the needle is in the center groove and that the retainer spring is pressed down the 'C' clip. Now soak the whole carburetor with spray cleaner, then blow out all passages with compressed air. Don't soak the rubber-tipped needle valve from under the float. On reassembly, set the idle mix screw 1-1/2 to 2 turns CCW from CW stop. Adjust for best idle after you get it running and warmed up. I hope this long winded explanation helps!

SOURCE: I am having running problems with my 2004 Yamaha

sounds like a partially plugged pilot or idle jet in the carb, either that or a vac leak. roadstars are known for intake leaks around the flange and make sure that the clamp at the back of the carb is fully tightend to the stop. roadstarclinic.com is a good source for information!