Anyone else got this Rattling noise - know what the issue is?

[LongBeard]

I've noticed a noise at 4500rpm to 5000rpm that almost sounds like a rattling noise. The noise is kinda hard to explain and is louder in 1st gear and gets quieter the higher in gear the bike is. 2nd gear is quieter 3rd gear is even quieter, 4th gear you can barely hear it, 5th gear is the quietest. The Spyder is a 2008 GS SM5 (manual). It has done this ever since I've owned it. The noise isn't there below 4500rpm and above 5000rpm. The bike still vibrates normally throughout all rpm speeds, so I am at a loss as to what this is. The noise sounds like it is coming from the engine area, but I cannot see any loose bolts or parts anywhere. I have spoken to my friends who know engines and they said it could be a number of things, being that it is a v-twin. Could be normal or could be a transmission issue as I do have an issue getting the bike to shift into a gear sometimes but not always. Sometimes it likes to hang in the gear I'm trying to shift out of on first attempt shifting. Second attempt always gets it to shift to another gear. Has anyone encountered this noise and figured out what the issue may be, (user error or an actual problem) if there is one, or does anyone have any idea what could be causing this noise or shifting issue? Thanks