i just rebuilt my 97 sportsman 500 but i have a small problem. the exhaust pipe is glowing red. i know that it is running lean but why?
i bought this used and it has a k&n air filter on it. i do not believe the the guy rejeted the carb. would the filter and no rejeting of the carb. give me the same results as a leaking intake or cracked boot? he gave me the filter box with the original filter in the box.

 

Did he drill some holes in the air box? If not I don't think that would be your problem. I just got done working on a Raptor the the header pipe was also glowing...I know I had the jeting right so I sprayed some carb cleaner around the carb boots....one of the boots had a small slit. This fixed the problem. Try that to see if you have any air leaks.

 

i put a brand new air box on so that is not it . i try some carb. cleaner like you suggested. thanks for the feed back.

 

Sounds like an air leak on the intake side. check all the fasteners and gaskets