what can i do to start my 06 400ex in the cold

[usmarine0311]

i have a 2006 400ex, with just an aftermarket pipe, it "WILL NOT" START IN THE COLD WEATHER what can i do to make it start. if anyone can help let me know thanks

[bmxatv]

did you re-jet the carb after you installed the pipe?

[yernkie]

Install a 42 pilot jet. That will help a lot.

[Toadz400]

Make sure to jet it correctly for the colder weather. You will definately need to go up a size on the pilot jet but I cannot help you with what to set your needle and main jet at.

[jonboy]

400ex Choke Removal (written by Knighttime & Lrd Mx400ex)
Description: Removing the choke plate to increase airflow. You maybe be thinking right now “How the heck will I get it started during winter time when I don’t have a choke?” Well the solution to that is 42 pilot jet, it solves the cold starting blues and you won’t need the choke any more.
Purpose: A nice increase in throttle response. There is more response and most likely a little added horsepower as well. You can feel improvement all through the power band.
Procedure
Step 1. Remove the rear fender, front fender, gas tank, air boot, and anything else that is needed to be removed to access/remove the carb.
Step 2. With the carb removed, remove the yellow choke lever. BE CAREFUL TO AVOID STRIPPING THE SOFT PHILIPS SCREW!
Step 3. Now look into the carb and you will see two gold screws, remove them. WHEN REMOVING THE SCREW HOLD THE CARB UPSIDE DOWN BECAUSE THERE WILL BE SMALL METAL SHAVINGS FROM REMOVING THE SCREW, THIS WAY THEY WON’T END UP IN YOUR ENGINE!
Step 4. Remove the clip (Figure #1) and the rod that attaches to the butterfly will slide right out.
Step 4. Remove the clip (Figure #1) and the rod that attaches to the butterfly will slide right out.

Step 5. The hole pictured in Figure #2 needs to be plugged. Put something over the hole and use a hose clamp to secure it. The hole is plugged in Figure #3.

Step 6. Put a 42 pilot in your 400 if you haven’t already done so. With the 42 pilot you will not need the choke. Just pump the throttle a few times before you hit the start button, and kind of feather the throttle at first. If you hear any popping' and cracking' or snapping sounds, it means you aren't jetted correctly.

[jonboy]

400ex Pilot Jet Installation/Exchange (written by Zingnut, editted by Lrd Mx400ex)
Purpose: To either correctly jet your bike for a new engine modification or to put in a 42 pilot jet to cure winter starting troubles.
Procedure
1. Turn your gas valve to off.
2. Start the quad and let it idle till it dies from lack of gas.
3. Remove the rear seat and rear fender.
4. Remove the two 5mm allen head bolts from the front plastic.
5. Remove the four 10mm bolts that are under the front fender.
6. Take off gas cap.
7. Remove the plastic gas tank cover.
8. Pull the front fender forward and out of the way of the gas tank.
9. Remove the two 10mm gas tank bolts and two rubber straps that are one either side of the gas tank.
10. Remove the gas line from the gas valve.
11. Remove the gas tank.
12. Remove the 10mm bolt on the air filter box and then loosen the screw clamp on the carb and airboot.
13. Remove the clear catch container from the clutch side of black air filter tube.
14. Remove the push lock from the clear plastic intake tube.
15. Pull off the air filter and clear intake tube.
16. Loosen the screw clamp on the motor side of the carb.
17. Remove the carb.
18. Remove the four phillips head screws from the bottom of the carb (see Figure #1).

19. Remove the plastic ring from the main jets (see Figure #2).

20. Gently remove the Pilot Jet from the carb (see Figure #3).

21. Gently screw in the new #42 Pilot Jet. DO NOT OVER TIGHTEN IT!
22. Put your ATV back together using these directions in reverse.

[Toadz400]

I would not advise removing the choke for added "performance". It's there for a reason and the carb is designed to have it in there. Also, complete teardown of your quad to change out jets are definately not needed on the 400EX. Taking off the seat/plastics is all I really needed to change the needle and loosening up the intake clamps on both sides of the carb and twisting it to the side are all that's needed for changing out the main and pilot jet.

[HondaEXrider22]

Choke it, pump the gas a few times, hit starter with a little gas.