Join Date: Oct 2018
Location: Prescott, Wi. Upper Ms.River bluff country
Sounds like a vacuum leak that seals itself after expanding. I'm not familiar with the 1000's but if it has a fuel pump, immersed or remote, It may make more noise when cold. The 650s, like some other makes, make a whistling sound from the cams/cam chain interaction.
"It is amazing what you can accomplish if you are not concerned with who gets the credit"- Patrick Griffin
"I never said half of that stuff."-Confucius