The manual wants it to idle at 1,500
What manual are you reading? Are you sure its for a Valkyrie? 1,500 is way too high for idle. Now that being said what ever idle speed you set it at, you have to set the idle at operating temperature. When cold it will idle much slower and the idle speed will increase as it warms up. If you can adjust it to idle at 900-1,000 at cold start up, it will be racing at idle once it warms up.
Hope this helps