were you useing a digital tach? Single cylinder engines do bounce up and down 200 RPM at idle as every time the pistion fires it speeds up to around 1,300 then at the top of the compression stroke its back down to 1,100. Perfectly normal for a large single cylinder thumper

 

It is a digital tach. one that I connect to the spark plug wire.

I would hate to know I had to adjust pilot screws everyday, my hands are a little big to fit in there, there must be a secret.