popping on start-ups

[KBROOKS400ex]

i have a 2000 trx 400ex with a hmf slip-on, a k&n, rev box and when i go to start it up it starts but then it will sometimes back fire and blow out black smoke i know it getting to much fuel and i have a 155 main and a 45 pilot and i think its still getting to much fuel any ideas let me know thanks.

[BEAVER.989]

You're definately too rich. Are you running with or without the airbox lid?

If you're running with the lid on I'd suggest backing down to a 40 or 42 pilot. With the 40 I'd go 2 1/2 to 3 1/2 turns out on the fuel screw... With the 42 I'd try 1 1/2 to 2 1/2 turns out.

You may even want to try a 152 main if you're still using the lid.

[RIDEREDson]

155 is too rich. So is your pilot. With the lid on, choke, K&N, and slip on I had a stock pilot and a 146 main.

Since I removed the choke and airbox lid I had to bump up to a 152 main and 42 pilot. Just to give you an idea.

[KBROOKS400ex]

alright thanks for the info ill try out those jets tomarrow before i leave for a riding trip in the upper pennisula of michigan thanks