400 rancher hard to start when warm

I had an 05 rancher at 400 that we recently sold to a friend.

he has stated that it is starting hard after it is warmed up. i dont know if he has done anything like clean the carb and such on it but i know i took very good care of it when i had it.

i wouldnt think that the carb is dirty but it is possible that it might be.

in the mean time, anyone else had an issue with it and have a remedy?

Thanks,
Steve

sounds like the valves need adjusted.

always adjust valves when motor is completely cool. who wants to work on a hot motor any way lol.