Hello Ethel it's me again

I have a question for ALL you VALK HEADS
My Valk has been running just fine EXCEPT

it will idle at 1000 rpms for weeks. Then all of a sudden I will come to a stop and it will stumble with the idle at about 600-700 rpm's. I will adjust it back to 1000 rpms and it will run fine for a couple days. Then when I got home last night and pulled her into the Biker Barn and put her in neutral she was idleing at about 1200/1300 rpms, readjust back to 1000 RPM's, rode to work and all is well... ???
This is a continious cycle of events , Will run great for weeks at a time but then,,,
Obvious question

Why is she doing that?
Thanks for your input and suggestions

Wewaman