MY IDLE SCREW FELL OUT WHILE RIDING REPLACED SCREW AND NOW AT HIGH RPMS EXTREME BOGGING DOWN FROM 2ND GEAR ON WITH SOME BACKFIRING. ITS A 1990 LT500R. ADJUSTED AIR SCREW NUMEROUS TIMES RUNS BEST WHEN ALL THE WAY IN. REALLY DONT KNOW WHATS GOING ON. PLEASE HELP I JUST BOUGHT BIKE AND LOVE TOO RIDE AND DONT REALLY HAVE ANY EXTRA $ TO SPEND. IF ANY FELLOW ZILLA OWNERS HAVE HAD THIS PROBLEM PLEASE TELL ME HOW TO FIX IT OR WHATS BEST TO DO.THANKS FOR HELPING!!!!!!!!!

 

how did it run before the screw fell out? How many turns out was the screw before it fell out? These are some questions that need to be answered first. It could be simply that you misadjusted the screw when you re-installed it. That's all it sounds like, or your jetting could be slightly off.

 

IT RAN FINE NOT SURE AS TO HOW MANY TURNS SCREW WAS OUT PLEASE SUGGEST WHAT JETTING INFO I MAY NEED THANKS MAN

 

There is also a spring and a o-ring that you need to purchase also that goes on the screw. Sounds like you didn't get all the parts so that is probably your problem. This should help you with the parts you need.
part finder

 

charliec........Please turn your Caps Lock off.........

 

Have all parts bought screw,o-ring,and screw did compression test its 120 after 15 kicks while cold throttle wide open.