I was waiting for my Pizza last night the same as a 600 Kwakka. When he rode off with his, he accelerated hard and it sounds a bit off then as the revs picked up, there was a really high pitched whistle that came out until he changed up...

Any idea what would make this noice?

Also, a pizza box fits very neatly over the dash of my CBR1000f and doesn't move when I turn the handle bars

 

Could just be the exhaust, but usually, a whistle noise is a vacuum leak. Could be one or more of his sync caps are missing. I heard that they fall off the 900RR motor quite easily. Pizza, yum.