carb problems

I went out and tried to start my 99yz400 yesterday and i had to kick it over about 15 times before it would start it has always started on the 2nd kick. I have recently put on a pro circuit pipe on it and had the carb cleaned and jetted by the local bike shop.And now it backfires when it decelerates and when it finally does start it runs for about 3 seconds and dies it will do that about 5or6 times before it will stay running at an idle then if you barley touch the throttle it will die.also when i went to turn the idle up it will go up for about 2 seconds then back down to where it was please help

Try adjusting the pilot screw on the bottom of the carb bowl. It takes a VERY short and small screw driver. See how many turns it is from all the way in. Back it out 1/4 turn at a time from what the shop set it to and check the response. Also, find out if they changed jets and what is in it. You may need to go back to what you had before. Look for any vacuum leaks too.

If all else fails, take it back and make them fix it.

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